Synlett via MedWorm.com MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Synlett' source. Mon, 06 Feb 2012 12:55:19 +0100 Expedient Microwave-Assisted Synthesis of Novel 6-Substituted 5-Alkoxy(benzyloxy)-3,6-dihydro-2H-1,3,4-oxadiazin-2-ones http://www.medworm.com/index.php?rid=5663904&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290160 SynlettDOI: 10.1055/s-0031-1290160Novel 6-substituted 5-alkoxy(benzyloxy)-3,6-dihydro-2H-1,3,4-oxadiazin-2-ones have been prepared in good yields and very short reaction times by intramolecular cyclization of α-hydroxyhydrazonates in the presence of sodium ethoxide under microwave irradiation.[...]© Georg Thieme Verlag Stuttgart · New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5663904 Fri, 03 Feb 2012 05:00:00 +0100 5663904 Synform issue 2012/02 http://www.medworm.com/index.php?rid=5655912&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289997 Synlett 2012; 23: A10-A19DOI: 10.1055/s-0031-1289997© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.Article in Thieme eJournals:Table of contents (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5655912 Wed, 01 Feb 2012 05:00:00 +0100 5655912 Facile N-Urethane-Protected α-Amino/Peptide Thioacid Preparation Using EDC and Na2S http://www.medworm.com/index.php?rid=5655911&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0030-1290331 Synlett 2012; 23: 482-482DOI: 10.1055/s-0030-1290331© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5655911 Wed, 01 Feb 2012 05:00:00 +0100 5655911 TIPSOTf-Promoted Tandem Reaction through Rearrangement of Epoxides into Aldehydes with Selective Alkyl Migration Followed by Prins-Type Cyclization to Cyclopentanes http://www.medworm.com/index.php?rid=5643480&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290324 SynlettDOI: 10.1055/s-0031-1290324AbstractThe tandem reaction of trisubstituted epoxides to cyclopentanes promoted by TIPSOTf in nitromethane has been found. It consists of stereospecific rearrangement of epoxides into aldehydes accompanied with selective alkyl migration and subsequent Prins-type cyclization of the aldehydes generated to cyclopentanes.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5643480 Fri, 27 Jan 2012 05:00:00 +0100 5643480 Abnormal and Direct para-Trifluoroacetylation of Branched Alkyl Phenyl Ketones by Magnesium-Promoted Reductive Aromatic Substitution http://www.medworm.com/index.php?rid=5643479&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290325 SynlettDOI: 10.1055/s-0031-1290325AbstractMagnesium-promoted reduction of branched alkyl phenyl ketones in the presence of ethyl trifluoroacetate and chlorotri­methylsilane in N,N-dimethylformamide (DMF), followed by air oxidation, and the subsequent treatment of tetrabutylammonium fluoride brought about selective and efficient formation of the corresponding aromatic para-substituted diketones possessing a tri­fluoroacetyl group in good yields through abnormal addition toward the para positions of the aromatic ketones in good yields.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5643479 Fri, 27 Jan 2012 05:00:00 +0100 5643479 Organocatalytic Conversion of Ribose and Other Protected Carbohydrate Derivatives into 2-Deoxy-lactones http://www.medworm.com/index.php?rid=5643478&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290327 We report the simultaneous reduction of the 2-position and oxidation of the anomeric position in several protected furanosyl and pyranosyl sugar derivatives, mediated through NHC catalysis. This reaction allows the one-step access to highly valuable 2-deoxy-sugars from abundant 2-oxygenated sugar derivatives.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5643478 Fri, 27 Jan 2012 05:00:00 +0100 5643478 Combining Two-Directional Synthesis and Tandem Reactions, Part 17: Expedient Formation of Functionalised Azabicycles http://www.medworm.com/index.php?rid=5643477&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290138 SynlettDOI: 10.1055/s-0031-1290138AbstractSynthesis of a range of functionalised azabicycles from simple linear keto dienoates has been achieved using a tandem enamine formation/Michael addition/aza-Michael addition reaction.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5643477 Fri, 27 Jan 2012 05:00:00 +0100 5643477 Novel Photolabile Protecting Group for Phosphate Compounds http://www.medworm.com/index.php?rid=5643476&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290326 SynlettDOI: 10.1055/s-0031-1290326AbstractA novel photolabile protecting group, thiochromone S,S-dioxide, containing the diazomethyl group for protection of phosphate derivatives is described. Deprotection of the successfully protected phosphate derivatives proceeded smoothly under photoirradiation using an ultrahigh-pressure mercury lamp to recover the corresponding phosphates quantitatively, and the photoproduct derived from the thiochromone derivative showed high fluorescence intensity.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5643476 Fri, 27 Jan 2012 05:00:00 +0100 5643476 Synthetic Study of Versipelostatin A: Synthesis of the Spirotetronate Unit Starting from Pulegone http://www.medworm.com/index.php?rid=5634971&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290204 SynlettDOI: 10.1055/s-0031-1290204AbstractThe synthesis of the spirotetronate unit of versipelostatin A, a down-regulator of molecular chaperone GRP78, was achieved in ten steps starting from pulegone, via the Johnson-Claisen rearrangement. A model study of the coupling reaction with the octalin unit was also performed.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634971 Thu, 26 Jan 2012 05:00:00 +0100 5634971 Palladium-Mediated Highly Regio- and Stereoselective Intermolecular β-Arylation on Allylic Alcohols: Synthesis of Functionalized Allylic Alcohols http://www.medworm.com/index.php?rid=5634970&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290203 SynlettDOI: 10.1055/s-0031-1290203AbstractAn efficient and highly regio- and stereoselctive Pd-catalyzed β-arylation method for the formation of β-aryl allylic alcohols, employing aryl iodides, 1-bromo-2-iodobenzenes, and 2-bromobezaldehydes as coupling partners, is presented. The β-aryl allylic alcohols formed in this Pd-catalyzed transformation is unexpected under conventional Jeffery conditions without the assistance of silver salt. It is proposed that the reaction is substrate controlled, and the selective formation of the product depends on the size or nature of the substituent at the ortho position on the aromatic ring of the allylic alcohol part.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Sourc... Synlett journals http://www.medworm.com/rss/comments.php?id=5634970 Thu, 26 Jan 2012 05:00:00 +0100 5634970 NHC-Catalyzed Chemo- and Regioselective Hydrosilylation of Carbonyl Derivatives http://www.medworm.com/index.php?rid=5634963&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290208 SynlettDOI: 10.1055/s-0031-1290208AbstractThe hydrosilylation of carbonyl derivatives has been explored by the activation of diphenylsilane in the presence of a catalytic amount of an N-heterocyclic carbene (NHC). Presumably, a hypervalent silicon intermediate featuring strong Lewis acid character allows dual activation of both the carbonyl moiety and the hydride at the silicon center. Reduction under mild conditions could be accomplished using this organocatalytic process. Some interesting selectivities have been encountered.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634963 Thu, 26 Jan 2012 05:00:00 +0100 5634963 New Approach to Flavonols via Base-Mediated Cyclization: Total Synthesis of 3,5,6,7-Tetramethoxyflavone http://www.medworm.com/index.php?rid=5634962&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290207 SynlettDOI: 10.1055/s-0031-1290207AbstractA new methodology for the synthesis of flavonols is described. The key step is a base-mediated cyclization-isomerization-elimination reaction which results in the formation of flavonols. Using this strategy, three flavonols are synthesized and characterized.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634962 Thu, 26 Jan 2012 05:00:00 +0100 5634962 Diphenylvinylsulfonium Triflate http://www.medworm.com/index.php?rid=5634973&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290134 SynlettDOI: 10.1055/s-0031-1290134© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634973 Wed, 25 Jan 2012 05:00:00 +0100 5634973 Palladium-Catalyzed Regioselective Arylation of Arene C-H Bond Assisted by the Removable 2-Pyridylsulfinyl Group http://www.medworm.com/index.php?rid=5634972&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290320 SynlettDOI: 10.1055/s-0031-1290320AbstractA palladium-catalyzed arylation of arene C-H bond assisted by a removable 2-pyridylsulfinyl group is described. The reaction employs aryltrifluoroborates as the arylation reagent, leading to the corresponding products in moderate to good yield with broad substrate scope. The directing group can be removed or converted to other useful functionalities, which showcases the potential synthetic application of the methodology.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634972 Wed, 25 Jan 2012 05:00:00 +0100 5634972 Direct Synthesis of α-Amino Amides from N-Alkyl Amines by the Copper-Catalyzed Oxidative Ugi-Type Reaction http://www.medworm.com/index.php?rid=5634969&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290319 SynlettDOI: 10.1055/s-0031-1290319Abstractα-Amino amides can be accessed directly form N-alkyl amines by the isocyanide-compatible oxidative copper-peroxide conditions even in the presence of water. Various functional groups are tolerated in the reaction, leading to the synthesis of various α-amino amides in moderate yield. A plausible mechanism is proposed in which an oxidative Ugi-type three-component pathway is supposed to be involved.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634969 Wed, 25 Jan 2012 05:00:00 +0100 5634969 A Unique Approach to Catalyst-Free, One-Pot Synthesis of Spirooxindole-Pyrazolines http://www.medworm.com/index.php?rid=5634968&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290322 SynlettDOI: 10.1055/s-0031-1290322AbstractA pseudo-five-component synthesis of spirooxindole-pyrazolines via a one-pot and catalyst-free reaction under mild conditions is reported. The 1,1-bishydrazino-2-nitroethylene intermediate generated in situ from the addition of aqueous hydrazine to 1,1-bis(methylthio)-2-nitroethylene is trapped by two equivalents of isatin derivatives to obtain the title compounds.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634968 Wed, 25 Jan 2012 05:00:00 +0100 5634968 Diaryliodonium(III) Salts: Arylating Agents http://www.medworm.com/index.php?rid=5634967&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290133 SynlettDOI: 10.1055/s-0031-1290133© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634967 Wed, 25 Jan 2012 05:00:00 +0100 5634967 N-Heteropentacenes and N-Heteropentacenequinones: From Molecules to Semiconductors http://www.medworm.com/index.php?rid=5634966&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290323 SynlettDOI: 10.1055/s-0031-1290323AbstractN-Heteropentacenes and their derivatives have been recently discovered as a new family of organic semiconductors exhibiting high performance in organic field effect transistors (OFETs). Introducing nitrogen atoms to the pentacene moiety leads to a large number of structurally related Ï€-backbones with tunable electronic structures, stability, solubility, and molecular packing. This gives considerable freedom when designing organic semiconductors and provides good opportunities for studying structure-property relationships. In this account, efforts on developing N-heteropentacenes and N-heteropentacenequinones as organic semiconductors are reviewed, with focus on the recent work of our own group.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArtic... Synlett journals http://www.medworm.com/rss/comments.php?id=5634966 Wed, 25 Jan 2012 05:00:00 +0100 5634966 Scaffolding Catalysis: Expanding the Repertoire of Bifunctional Catalysts http://www.medworm.com/index.php?rid=5634965&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290321 This article outlines our group’s recent efforts to use reversible covalent bonding to induce an intramolecular reaction, allowing for rate acceleration as well as control of the selectivity in the desymmetrization of 1,2-diols.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634965 Wed, 25 Jan 2012 05:00:00 +0100 5634965 Copper(II)-Catalyzed O-Arylation of Tertiary Alcohols with Arylbismuth(III) Reagents: A Convenient System for Aryl Transfer http://www.medworm.com/index.php?rid=5634964&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290205 SynlettDOI: 10.1055/s-0031-1290205AbstractCopper(II)-catalyzed O-arylation of tertiary alcohols with various triarylbismuth reagents was investigated. A convenient and efficient system for aryl ether formation of tertiary alcohols has been developed through the in situ oxidation of stable triarylbismuth(III) to triarylbismuth(V) species using PhI(OAc)2 as the oxidant in the presence of a catalytic amount of copper(II) acetate.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634964 Wed, 25 Jan 2012 05:00:00 +0100 5634964 A Regioselective Catalyst- and Additive-Free Synthesis of β-Keto Sulfones from Aryl Acetylenes and Sodium Arenesulfinates http://www.medworm.com/index.php?rid=5634961&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290318 SynlettDOI: 10.1055/s-0031-1290318AbstractA facile and regioselective procedure for the preparation of β-keto sulfones has been developed through a simple reaction of aryl acetylenes and sodium arenesulfinates in nitroethane as a solvent at 50 ËšC. The procedure is catalyst- and additive-free and shows a wide range of functional-group tolerance. In this system the formation of new C-O and C-S bonds occurs in a one-pot procedure.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634961 Wed, 25 Jan 2012 05:00:00 +0100 5634961 Three-Step Synthesis of (Thio)xanthene and Dibenzothiepine/Dibenzoxepine by an Intramolecular Mizoroki-Heck Reaction of Diaryl (Thio)Ethers http://www.medworm.com/index.php?rid=5634960&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290317 We present a novel three-step protocol for preparing xanthene/thioxanthene and dibenzothiepine/dibenzoxepine from readily available starting materials. The Mizoroki-Heck cyclization as the final step was optimized to afford full conversion of the corresponding diaryl (thio)ethers and furthermore to achieve reasonably good selectivity between the 6-exo and the 7-endo products.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5634960 Wed, 25 Jan 2012 05:00:00 +0100 5634960 Platinum-Catalyzed Transformation of Alkyne Allyl Alcohols and Sulfonamides into Heterotricyclo[3.3.1.02,8]nonanes http://www.medworm.com/index.php?rid=5616606&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290314 SynlettDOI: 10.1055/s-0031-1290314AbstractPlatinum chloride catalyzed cycloisomerization of alkyne allyl alcohols and alkyne allyl sulfonamides gave new cycloisomerization products, diaza-, azaoxa-, and dioxatricyclo-[3.3.1.0²,8]nonanes, in reasonable to high yields.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616606 Thu, 19 Jan 2012 05:00:00 +0100 5616606 Rh(I)-Catalyzed Cyclocarbonylation of Enynes with Glyceraldehyde: An Available Carbonyl Source Derived from Sugar Alcohols http://www.medworm.com/index.php?rid=5616605&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290311 SynlettDOI: 10.1055/s-0031-1290311AbstractCatalytic cyclocarbonylation reactions using a glyceraldehyde derivative as a carbonyl source are described. The rhodium(I)-catalyzed reaction of enynes with glyceraldehyde acetonide gave bicyclic cyclopentenones as the products. This presents an interesting use of a sugar alcohol derived carbon resource as well as a convenient procedure for the cyclocarbonylation of enynes.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616605 Thu, 19 Jan 2012 05:00:00 +0100 5616605 Synthetic Utility of Chiral Bis(oxazolinyl)phenyl Transition-Metal Complexes http://www.medworm.com/index.php?rid=5616604&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290315 SynlettDOI: 10.1055/s-0031-1290315AbstractTransition-metal complexes with a chiral bis(oxazolinyl)phenyl (Phebox) ligand can construct suitable chiral environments around metal centers. Thus far, a number of transition-metal complexes in the range of early to late metals have been prepared via transmetalation, cyclometalation, and oxidative addition. The fundamental properties and catalytic activities of the resulting Phebox complexes have been extensively investigated. In particular, the Phebox-Rh and Phebox-Ru complexes were found to serve as efficient and selective catalysts in asymmetric reactions for carbon-carbon bond formation, reduction of unsaturated bonds, and functionalization reactions. In this Account, we summarize details of the Phebox complexes in terms of preparations, coor... Synlett journals http://www.medworm.com/rss/comments.php?id=5616604 Thu, 19 Jan 2012 05:00:00 +0100 5616604 Total Synthesis of Altenusin and Alterlactone http://www.medworm.com/index.php?rid=5616603&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290135 SynlettDOI: 10.1055/s-0031-1290135AbstractThe resorcylic lactone alterlactone, a mycotoxin produced by alternaria sp., was synthesized for the first time. The total synthesis was achieved in nine steps with 69% yield starting with acetal-protected phloroglucinic acid and 6-bromopiperonal, where the longest linear sequence consists of five steps. Key step is a ­Suzuki coupling used for the construction of the central biaryl bond. When the final deprotection with cleavage of benzyl ethers (yielding unprotected alterlactone) was performed in a less polar solvent the biaryl mycotoxin altenusin was obtained.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616603 Thu, 19 Jan 2012 05:00:00 +0100 5616603 Synthesis of Aryl-Substituted 1,4-Dihydroquinolines by [4+2] Cycloaddition of Benzyne with 1-Azadienes http://www.medworm.com/index.php?rid=5616602&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290137 SynlettDOI: 10.1055/s-0031-1290137AbstractThe synthesis of aryl-substituted 1,4-dihydroquinolines can be achieved using a [4+2] cycloaddition between benzyne and various aryl-substituted 1-azadienes. The conditions are tolerated by N-aryl-, alkyl-, tosyl-, and tert-butoxycarbonyl-protected 1-azadienes. A short synthesis of the fungal metabolite 3-O-methylviri­dicatin is reported.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616602 Thu, 19 Jan 2012 05:00:00 +0100 5616602 Reductive Ring Cleavage of Nonconjugated Δ²-Isoxazolines to β-Hydroxy Ketones with Aluminum and Copper(II) Chloride http://www.medworm.com/index.php?rid=5616601&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290310 SynlettDOI: 10.1055/s-0031-1290310AbstractA facile, economic, and efficient protocol for the reduction of nonconjugated Δ²-isoxazolines to the corresponding β-hydroxy ketones using Al/CuCl2 as the reducing agent has been developed. The method is both rapid and complete requiring less than ten minutes to attain total ring cleavage. This is the first example of using an in situ prepared Al/Cu couple in organic synthesis.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616601 Thu, 19 Jan 2012 05:00:00 +0100 5616601 A Facile Synthesis of 5-Halopyrimidine-4-Carboxylic Acid Esters via a Minisci Reaction http://www.medworm.com/index.php?rid=5616600&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290136 SynlettDOI: 10.1055/s-0031-1290136AbstractThis paper reports the synthesis of various 5-halopyrimidine-4-carboxylic acid esters via the Minisci homolytic alkoxycarbonylation of 5-halopyrimidines. The reaction was found to be highly regioselective, allowing the one-step synthesis of useful amounts (>10 g) of ethyl 5-bromopyrimidine-4-carboxylate where other methods proved difficult. Ethyl 5-bromopyrimidine-4-carboxylate was used for the preparation of potent CK2 inhibitors including CX-5011. This work represents an interesting application of radical chemistry for the preparation of pharmacologically active molecules.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616600 Thu, 19 Jan 2012 05:00:00 +0100 5616600 Palladium-Catalyzed Ring Opening of Aminocyclopropyl Ugi Adducts http://www.medworm.com/index.php?rid=5616599&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290312 SynlettDOI: 10.1055/s-0031-1290312AbstractThe ring opening of aminocyclopropanes triggered by activation with an intramolecular arylpalladium(II) iodide complex is an interesting strategy for the synthesis of nitrogen heterocycles and a valuable Ugi postcondensation-type transformation. Six- and seven-membered-ring cyclic enamines may be obtained.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616599 Thu, 19 Jan 2012 05:00:00 +0100 5616599 Stereoselective Synthesis of vic-Halohydrins via l-tert-Leucine-Catalyzed syn-Selective Aldol Reaction http://www.medworm.com/index.php?rid=5616598&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290316 SynlettDOI: 10.1055/s-0031-1290316Abstractl-tert-Leucine was found to be an effective organocatalyst for the asymmetric aldol reaction of chloroacetone. The stereoselective synthesis of vic-halohydrins was accomplished with excellent regioselectivity (>99%) to generate α-chloro-β-hydroxy ketones with high syn selectivity (syn/anti = 16:1) and enantioselectivity (up to 95% ee).[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616598 Thu, 19 Jan 2012 05:00:00 +0100 5616598 Dual Activation in Organocatalysis: Design of Tunable and Bifunctional Organocatalysts and Their Applications in Enantioselective Reactions http://www.medworm.com/index.php?rid=5616597&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290131 SynlettDOI: 10.1055/s-0031-1290131AbstractDual activation has been identified as an important concept in the field of asymmetric catalysis, especially asymmetric organocatalysis. A comprehensive account of the design of novel amino hydrogen-bonding organocatalysts and their successful applications in two classic carbon-carbon bond forming reactions, namely the asymmetric aldol and Michael reactions, is given. This account also covers work that uses known organocatalysts in the preparation of other important chiral molecules using the asymmetric Michael reaction as the key transformation by virtue of a dual activation strategy.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616597 Thu, 19 Jan 2012 05:00:00 +0100 5616597 Direct Vinylogous Aldol Reaction Triggered by Tetrabutylammonium Fluoride: A Highly Regioselective and Diastereoselective Addition of Cyclic β-Haloenals to Aromatic Aldehydes http://www.medworm.com/index.php?rid=5616596&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290313 SynlettDOI: 10.1055/s-0031-1290313AbstractA new type of direct vinylogous aldol addition between cyclic β-haloenals and aromatic aldehydes promoted by TBAF has been developed. The reaction was carried out under mild conditions to provide highly functionalized δ-hydroxy-β-halo-α,β-unsaturated aldehydes with high diastereomeric ratios and low to good yields.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5616596 Thu, 19 Jan 2012 05:00:00 +0100 5616596 Room-Temperature Palladium-Catalyzed Coupling of Heteroaryl Amines with Aryl or Heteroaryl Bromides http://www.medworm.com/index.php?rid=5568275&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290069 SynlettDOI: 10.1055/s-0031-1290069AbstractHeteroaryl amines readily undergo Buchwald-Hartwig amination reactions with a range of aryl and heteroaryl bromides at room temperature using t-BuXPhos Pd-precatalyst and NaOt-Bu. The pharmaceutically attractive biaryl amines are generally formed in short reaction times (0.5-16 h) and in good to excellent yields.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568275 Wed, 04 Jan 2012 05:00:00 +0100 5568275 Bidentate Lewis Acids as Catalysts for the Activation of 1,2-Diazenes in Organic Synthesis http://www.medworm.com/index.php?rid=5568269&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290132 SynlettDOI: 10.1055/s-0031-1290132AbstractA new concept for the catalysis of the inverse-electron-demand Diels-Alder (IEDDA) reaction of 1,2-diazenes using bidentate Lewis acid was recently reported by our group. The general catalytic principle is based on the simultaneous coordination of the bidentate Lewis acid to the 1,2-diazene moiety, lowering the LUMO to facilitate the cycloaddition step. Extrusion of N2 regenerates the catalyst and after elimination the aromatic product is obtained. In this account the development of this new catalytic principle is described and put into the general context of Lewis acid catalysis.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568269 Wed, 04 Jan 2012 05:00:00 +0100 5568269 Lithium Naphthalenide http://www.medworm.com/index.php?rid=5568267&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290127 SynlettDOI: 10.1055/s-0031-1290127© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568267 Wed, 04 Jan 2012 05:00:00 +0100 5568267 Phosphoric Trichloride http://www.medworm.com/index.php?rid=5568263&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290126 SynlettDOI: 10.1055/s-0031-1290126© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568263 Wed, 04 Jan 2012 05:00:00 +0100 5568263 Four-Component Synthesis of Indazole through Ugi-Azide Coupling http://www.medworm.com/index.php?rid=5568282&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290075 SynlettDOI: 10.1055/s-0031-1290075Abstractortho-Nitrobenzaldehyde and trimethylsilyl azide were used in a Ugi-Cadogan cascade towards tetrazolyl indazoles. After the Ugi step, the intermediate tetrazoles were not purified but directly heated with triethyl phosphite to form the final indazoles.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568282 Tue, 03 Jan 2012 05:00:00 +0100 5568282 Stereoselective, One-Pot, Three-Component Synthesis of 4-Aryltetrahydropyrans from Epoxides via Prins Cyclization Reaction http://www.medworm.com/index.php?rid=5568281&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290080 SynlettDOI: 10.1055/s-0031-1290080AbstractA three-component, one-pot synthesis of 4-aryltetra­hydropyrans from epoxides and homoallylic alcohols in arenes via Prins-Friedel-Crafts reaction, mediated by boron trifluoride etherate, has been developed. The reaction is diastereoselective and gives only all-cis diastereomers in moderate to good yields.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568281 Tue, 03 Jan 2012 05:00:00 +0100 5568281 New Reactions Exploring the Chemical Spaces of the Aldol Addition of Active Methylene Compounds http://www.medworm.com/index.php?rid=5568280&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289524 SynlettDOI: 10.1055/s-0031-1289524AbstractDuring research planning and the development of ideas, organic chemists intuitively work on the chemical space, even if they are often unaware of the nature and the extent of chemical space of organic reactions, in which they are moving. The exploration and the rational analysis of new chemical spaces originating from new tandem and multicomponent aldol additions of active methylene compounds can lead to the development of new efficient and environmentally friendly methodologies and to the synthesis of new libraries of highly functionalised compounds.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568280 Tue, 03 Jan 2012 05:00:00 +0100 5568280 Synthetic Protocols Mutually Applicable to 4-Oxoquinolines and 4-Oxo-1,8-naphthyridines: Synthesis of 1-Aryl-2-substituted and 1-Aryl-3-fluoro-4-oxoquinolines and 4-Oxo-1,8-naphthyridines http://www.medworm.com/index.php?rid=5568279&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290079 SynlettDOI: 10.1055/s-0031-1290079AbstractWe have achieved the synthesis of 1-aryl-2-substituted 4-oxoquinoline and 4-oxo-1,8-naphthyridine derivatives, which cannot be synthesized by known methods, via two useful synthons, 2-formyl-4-oxoquinoline and 2-methylsulfonyl-4-oxo-1,8-naphthyridine. We also succeeded in the synthesis of 1-aryl-3-fluoro-4-oxoquinoline by fluorocyclization of N-arylenaminone with Selectfluor® and potassium carbonate in DMF in a one-pot procedure. To the best of our knowledge, this is the first synthesis of 3-fluoro-4-oxoquinoline derivatives. We confirmed that these protocols were mutually applicable to the synthesis of 4-oxoquinoline and 4-oxo-1,8-naphthyridine derivatives.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of conte... Synlett journals http://www.medworm.com/rss/comments.php?id=5568279 Tue, 03 Jan 2012 05:00:00 +0100 5568279 Pd(II)-Catalyzed Direct Olefination of Arenes with Allylic Esters and Ethers http://www.medworm.com/index.php?rid=5568278&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290078 SynlettDOI: 10.1055/s-0031-1290078AbstractA convenient Pd(II)-catalyzed direct olefination of unactivated arenes with allylic esters and ethers via C-H activation was demonstrated. Under the typical conditions, various aryl-substituted allylic esters and ethers can be prepared.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568278 Tue, 03 Jan 2012 05:00:00 +0100 5568278 Synthetic Approach to the Chemical Isostere of O-Methyl Honokiol http://www.medworm.com/index.php?rid=5568277&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290076 SynlettDOI: 10.1055/s-0031-1290076AbstractWe established a synthetic method for the chemical isostere of the structurally unique natural product, 4′-O-methyl honokiol by replacing two allyl groups with two different alkyl groups with the aim of developing synthetic analogues of the chemical isostere. The key steps in this synthetic route are the Suzuki-Miyaura coupling reaction for the formation of the phenylpyridine moiety and the Stille coupling reaction for the stepwise introduction of two allyl groups.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568277 Tue, 03 Jan 2012 05:00:00 +0100 5568277 Efficient One-Pot Synthesis of 2-Substituted Benzimidazoles from Triacyloxyborane Intermediates http://www.medworm.com/index.php?rid=5568276&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290129 SynlettDOI: 10.1055/s-0031-1290129AbstractAn efficient one-pot synthesis of 2-substituted benzim­idazoles via triacyloxyborane intermediates is reported. The mild protocol is efficient and tolerant of acid-labile functional groups.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568276 Tue, 03 Jan 2012 05:00:00 +0100 5568276 One-Pot Synthesis of Fused Pyridazino[4,5-b][1,4]oxazepine-diones via Smiles Rearrangement http://www.medworm.com/index.php?rid=5568274&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290073 SynlettDOI: 10.1055/s-0031-1290073AbstractFused pyridazino[4,5-b][1,4]oxazepine-diones were easily obtained in moderate to excellent yields via Smiles rearrangement. The synthetic approach is supported by a one-pot coupling-Smiles rearrangement-cyclization process. This process has potential applications in the synthesis of biologically and medicinally relevant compounds.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568274 Tue, 03 Jan 2012 05:00:00 +0100 5568274 Intramolecular Conjugate Addition of α,β-Unsaturated Lactones Having an Alkanenitrile Side Chain: Stereocontrolled Construction of Carbocycles with Quaternary Carbon Atoms http://www.medworm.com/index.php?rid=5568273&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290074 SynlettDOI: 10.1055/s-0031-1290074AbstractAn efficient method for constructing carbocycles with all-carbon quaternary stereocenters has been developed on the basis of a stereoselective cyclization reaction of α,β-unsaturated lactones having an alkanenitrile side chain. Treatment of the substrate with lithium hexamethyldisilazide (LiHMDS) in the presence of triisopropylsilyl chloride (TIPSCl) led to the generation of the corresponding α-cyano carbanion species which readily underwent an intramolecular conjugate addition reaction. It was found that the combined use of trimethylsilyl trifluoromethanesulfonate (TMSOTf) and triethylamine is also effective for the cyclization ­reaction without using a strong base. Interestingly, different ste­reochemical outcomes were observed in the two ... Synlett journals http://www.medworm.com/rss/comments.php?id=5568273 Tue, 03 Jan 2012 05:00:00 +0100 5568273 Synthesis of the Antifungal Cyclic Peptides Tunicyclins C and D http://www.medworm.com/index.php?rid=5568272&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290071 SynlettDOI: 10.1055/s-0031-1290071AbstractThe first synthesis of the cyclic peptides tunicyclins C and D is described. Tunicyclin D is a potent antifungal agent, isolated from a traditional Chinese medicinal herb.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568272 Tue, 03 Jan 2012 05:00:00 +0100 5568272 Stereoselective Synthesis of Geometrically Strained, Oxindole-Appended Vinyl Cyclopropanes and Highly Substituted Cyclopentenes via Sulfur Ylide Cyclopropanation and Vinyl Cyclopropane Rearrangement http://www.medworm.com/index.php?rid=5568271&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290077 SynlettDOI: 10.1055/s-0031-1290077AbstractAn efficient diastereoselective synthesis of oxindole-­appended vinyl cyclopropanes from bromo isomerised Morita-Baylis-Hillman adducts of isatin with activated alkylidene and isatilidines via sulfur ylide cyclopropanation reaction have been achieved. The synthesised vinyl cyclopropanes have undergone vinyl cyclopropane rearrangement and [3+2] cycloaddition with an allene to afford dispiro bisoxindole bridged by cyclopentene and spirocyclopentene-2-oxindole-bridged spirocyclopropane-2-oxindole derivatives, respectively.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568271 Tue, 03 Jan 2012 05:00:00 +0100 5568271 Efficient Synthesis of Arylated Coumarins by Site-Selective Suzuki-Miyaura Cross-Coupling Reactions of the Bis(triflate) of 4-Methyl-5,7-dihydroxy­coumarin http://www.medworm.com/index.php?rid=5568270&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290072 SynlettDOI: 10.1055/s-0031-1290072AbstractArylated coumarins were prepared by site-selective ­Suzuki-Miyaura cross-coupling reactions of the bis(triflate) of 4-methyl-5,7-dihydroxycoumarin.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568270 Tue, 03 Jan 2012 05:00:00 +0100 5568270 Exploring α-Chromonyl Nitrones as 1,5-Dipoles http://www.medworm.com/index.php?rid=5568268&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290070 SynlettDOI: 10.1055/s-0031-1290070AbstractN-Phenyl-C-chromonyl nitrones 1 and the allenoate zwitterion 2, generated by addition of phosphine to acetylenedicarboxylates, undergo a cascade reaction sequence involving an unprecedented [5+3] annulation followed by deoxygenative rearrangement leading to dihydropyridine-fused benzopyrones. Unusual electronic control by the N-substituents of 1 directs the annulation pathway, leading to two different ring-systems.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568268 Tue, 03 Jan 2012 05:00:00 +0100 5568268 Titanium(IV) Enolates of 2-Nitrocarboxylic Esters and Their Oxidative Chlorination. A Convenient Route to α-Chloro-α-nitrocarboxylates http://www.medworm.com/index.php?rid=5568266&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290081 SynlettDOI: 10.1055/s-0031-1290081AbstractA new method for the synthesis of 2-chloro-2-nitrocarboxylic esters from 2-nitrocarboxylates is described. The procedure consists of the oxidative chlorination of titanium(IV) enolates of 2-nitro esters in the presence of ammonium nitrate. Esters of 2-chloro-2-nitrocarboxylic acids are formed in very good to quantitative yields. Application of this method for the chlorination of α,α′-dinitrodicarboxylates leads to α,α′-dichloro-α,α′-dinitrocarboxylic esters with high meso-diastereoselectivity. The absence of ammonium nitrate from the reaction mixture affects the reduction of nitro groups and leads to partial transformation of 2-nitrocarboxylic esters into 2-(hydroxyimino)carboxylates.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArti... Synlett journals http://www.medworm.com/rss/comments.php?id=5568266 Tue, 03 Jan 2012 05:00:00 +0100 5568266 Alkyne-Assisted Approach to the Formal Synthesis of Antibiotic Macrolide (-)-A26771B http://www.medworm.com/index.php?rid=5568265&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290130 SynlettDOI: 10.1055/s-0031-1290130AbstractA stereoselective formal synthesis of a 16-membered antibiotic macrolide (-)-A26771B is described starting from (R)-propylene oxide and (+)-diethyl tartrate. Key steps involved in this alkyne-assisted convergent approach are alkyne zipper reaction, Cadiot-Chodkiewicz coupling, and Yamaguchi macrolactonization.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5568265 Tue, 03 Jan 2012 05:00:00 +0100 5568265 Development of a Near Infrared Fluorescence Labeling Reagent: Synthesis of Indole-Functionalized Indocyanine Green Derivatives http://www.medworm.com/index.php?rid=5568264&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290139 SynlettDOI: 10.1055/s-0031-1290139AbstractWe have demonstrated a facile synthesis of functionalized indocyanine green (ICG) derivatives. Heteroatom-substituted indolenine was synthesized via SNAr reaction of 5-chloro-2,4-di­nitroanisole with 1,2-dimethyl-1-propenyl trimethylsilyl ether followed by reduction of the nitro groups. After the introduction of hydrophilic butanesulfonate moieties, homo- and heterocondensations with glutaconaldehyde dianilide provided symmetrical and unsymmetrical ICG derivatives, which exhibit near infrared (NIR) absorption and fluorescence emission similar to those of ICG. NIR fluorescence labeling reagent was synthesized using the amino group in the ICG derivative. The 1,3-dipolar cycloaddition with benzyl azide was performed utilizing copper nanoparticles tow... Synlett journals http://www.medworm.com/rss/comments.php?id=5568264 Tue, 03 Jan 2012 05:00:00 +0100 5568264 Remarkable Switch in the Regiochemistry of the Iodination of Anilines by N-Iodosuccinimide: Synthesis of 1,2-Dichloro-3,4-diiodobenzene http://www.medworm.com/index.php?rid=5532637&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290118 SynlettDOI: 10.1055/s-0031-1290118AbstractDirect iodination of anilines by NIS in polar solvents (such as DMSO) affords p-iodinated products with up to >99% ­regioselectivity. Switching to less polar solvents (such as benzene) in the presence of AcOH inverts this outcome toward dramatically increased or preferential generation of the o-isomers, also with up to >99% regioselectivity. This finding was exploited in the synthesis of 1,2-dichloro-3,4-diiodobenzene.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532637 Thu, 22 Dec 2011 05:00:00 +0100 5532637 ‘Pseudo-halide’ Derivatives of Grubbs- and Schrock-Type Catalysts for Olefin Metathesis http://www.medworm.com/index.php?rid=5532636&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290120 SynlettDOI: 10.1055/s-0031-1290120AbstractMetathesis has persisted through the years as a formidable synthetic approach to various unsaturated organic molecules and macromolecules. The 21st century developments in olefin metathesis continue to feature more efficient and selective, well-defined metathesis catalysts. Due to the easily regulated steric and electronic properties of ‘pseudo-halide’ derivatives, their study has launched a new milestone in ruthenium- and molybdenum-based catalysis. Synthesizing ‘pseudo-halide’ derivatives often entails replacing halide ligands with easily modified carboxylates, perfluorocarboxylates, phenoxides, isocyanates, isothiocyanates, pyridines, nitrates, and trifluoromethanesulfonates. This account elucidates the recent advances in ‘pseudo-halid... Synlett journals http://www.medworm.com/rss/comments.php?id=5532636 Thu, 22 Dec 2011 05:00:00 +0100 5532636 Oxidative Coupling of Tertiary Amines: Scope, Mechanism and Challenges http://www.medworm.com/index.php?rid=5532635&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290117 This article highlights the current scope of oxidative coupling reactions of tertiary amines. Emphasis has been placed on recent synthetic and mechanistic studies and suggests potential areas of improvement for the future.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532635 Thu, 22 Dec 2011 05:00:00 +0100 5532635 Synthesis of Highly Substituted Symmetrical 1,3-Dienes via Organocuprate Oxidation http://www.medworm.com/index.php?rid=5532634&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290116 SynlettDOI: 10.1055/s-0031-1290116AbstractOxidation of alkenyl organocuprates formed from alkenyl halides allows the formation of highly substituted symmetrical 1,3-dienes. Cuprates formed from organolithiums and Grignard reagents can be tolerated and the reaction proceeds with retention of alkenyl geometry.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532634 Thu, 22 Dec 2011 05:00:00 +0100 5532634 Novel Phosphate Derivatives as Scaffolds for the Preparation of Synthetic Phosphoserine-Based Peptides Using the Fmoc/t-Bu Solid-Phase Strategy http://www.medworm.com/index.php?rid=5532632&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290119 SynlettDOI: 10.1055/s-0031-1290119AbstractSynthetic peptides incorporating analogues of phosphoserine are valuable tools for the study of protein kinases and phosphatases. In addition, derivatives of naturally occurring peptides incorporating phosphate groups may have interesting biological properties. Herein we describe a new Fmoc/t-Bu solid-phase peptide synthesis (SPPS) strategy for the convenient generation of phosphoserine-based peptides. A proof-of-concept synthesis that demonstrates the feasibility of this approach is presented.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532632 Thu, 22 Dec 2011 05:00:00 +0100 5532632 Reduce to the Maximum: Truncated Natural Products as Powerful Modulators of Biological Processes http://www.medworm.com/index.php?rid=5532631&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290125 SynlettDOI: 10.1055/s-0031-1290125AbstractThis account describes several examples from the literature, as well as from our own work, of efforts to reduce the structural complexity of natural products through truncation by organic synthesis. This process, sometimes called diverted total synthesis or function oriented synthesis, also aims to deliver improved compounds for clinical evaluation. The discussed examples from the literature of this type of chemical editing are the truncation of halichondrin B to E7389/eribulin, bryostatin 1 to the bryologs, migrastatin to the migrastatin core, macfarlandin E, and somatostatin (SRIF14) to L-363,301 and octreotide. From our work, efforts on the truncation of anguinomycin/leptomycin, farinosone C to tyrosinol propionamide, and anachelin to the anache... Synlett journals http://www.medworm.com/rss/comments.php?id=5532631 Thu, 22 Dec 2011 05:00:00 +0100 5532631 Editorial http://www.medworm.com/index.php?rid=5532630&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0030-1290128 Synlett 2012; 2012: 45-45DOI: 10.1055/s-0030-1290128Article in Thieme eJournals:Table of contents (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532630 Thu, 22 Dec 2011 05:00:00 +0100 5532630 α-Formylation of α-Substituted Ketones http://www.medworm.com/index.php?rid=5532629&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290121 SynlettDOI: 10.1055/s-0031-1290121AbstractThe reaction of (chloromethylene)dimethylammonium chloride (generated in situ from oxalyl chloride and DMF) with α-substituted ketones in CH2Cl2, followed by workup with aqueous NaHCO3, gave β-keto aldehydes containing an α-quaternary centre (8-88% yield).[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532629 Thu, 22 Dec 2011 05:00:00 +0100 5532629 New Routes to Lipophilic Amino Acids: Synthesis of Alkynyl and Fluoro-Containing Alanine Derivatives http://www.medworm.com/index.php?rid=5532628&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290123 SynlettDOI: 10.1055/s-0031-1290123AbstractBranched α-amino acids incorporating an alkynyl group have been prepared by copper-catalysed reaction of a serine-derived organozinc reagent with bromoallenes. Substantial improvements to our previously reported Negishi cross-coupling of the serine-­derived organozinc reagent with cycloalkenyl triflates are possible using a combination of LiCl and SPhos as ligand. Finally, we report a preliminary example of addition of HF to cycloalkenyl alanine ­derivatives, leading to the corresponding tertiary fluoride.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532628 Thu, 22 Dec 2011 05:00:00 +0100 5532628 Sultam Thioureas: Synthesis and Antiviral Activity Against West Nile Virus http://www.medworm.com/index.php?rid=5532627&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290124 SynlettDOI: 10.1055/s-0031-1290124AbstractThe syntheses of eleven sultam thioureas, including nine new compounds, are described. These compounds were synthesized from thioureas and include the first sultam thioureas in which the two thiourea nitrogen groups are not identical. In addition, the first X-ray crystal structures of sultam thioureas and the antiviral activity of these compounds against West Nile virus (WNV) are reported.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532627 Thu, 22 Dec 2011 05:00:00 +0100 5532627 Synform issue 2012/01 http://www.medworm.com/index.php?rid=5532638&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1259222 Synlett 2012; 2012: A1-A9DOI: 10.1055/s-0031-1259222© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.Article in Thieme eJournals:Table of contents (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532638 Wed, 21 Dec 2011 05:00:00 +0100 5532638 Enantioselective Intramolecular Hydroamination of N-Alkenyl Ureas [nl]Catalyzed by tropos BIPHEP-Gold(I) Complexes with Au-Au Interaction http://www.medworm.com/index.php?rid=5532633&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290122 Synlett 2012; 2012: e1-e1DOI: 10.1055/s-0031-1290122© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5532633 Wed, 21 Dec 2011 05:00:00 +0100 5532633 The Wieland-Miescher Ketone: A Journey from Organocatalysis to Natural Product Synthesis http://www.medworm.com/index.php?rid=5511827&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290115 SynlettDOI: 10.1055/s-0031-1290115© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5511827 Fri, 16 Dec 2011 05:00:00 +0100 5511827 Rongalite http://www.medworm.com/index.php?rid=5500673&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290104 SynlettDOI: 10.1055/s-0031-1290104© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5500673 Tue, 13 Dec 2011 05:00:00 +0100 5500673 Molecular Iodine http://www.medworm.com/index.php?rid=5500672&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290114 SynlettDOI: 10.1055/s-0031-1290114© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5500672 Tue, 13 Dec 2011 05:00:00 +0100 5500672 Low Catalyst Loadings for Copper-Catalyzed O-Arylation of Phenols with Aryl and Heteroaryl Halides under Mild Conditions http://www.medworm.com/index.php?rid=5500671&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290110 SynlettDOI: 10.1055/s-0031-1290110AbstractA practical and mild strategy has been developed for the cross-coupling of O-arylation of phenol with differently substituted aryl halides and heteroaryl iodides using low catalyst loading of copper iodide under low operating temperature in DMF with TMHD as the ligand and Cs2CO3 as the base. This method tolerates a variety of functional groups including sterically hindered phenols and heteroaryl iodides to afford products in good to excellent yields (up to 95%).[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5500671 Tue, 13 Dec 2011 05:00:00 +0100 5500671 Cluster Preface: Gold Catalysis for Organic Synthesis: Opportunities Abound http://www.medworm.com/index.php?rid=5500670&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290112 SynlettDOI: 10.1055/s-0031-1290112AbstractIn the past decade, the reactivity of homogeneous gold catalysts have been explored, developed and harnessed by organic chemists. Among other reactivities, gold complexes can act as mild Ï€-acid catalysts, participate in backbonding to generate intermediates with unique reactivity, and promote oxidative coupling reactions. Modification and tuning of the ligands in these complexes can modify reactivity and result in highly selective reactions. This relatively young field is still developing and entirely new modes of ­reactivity are being discovered.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5500670 Tue, 13 Dec 2011 05:00:00 +0100 5500670 Enantioselective Protonation in the Sulfa-Michael Addition Using Chiral Squaramides as Hydrogen-Bonding Organocatalysts http://www.medworm.com/index.php?rid=5500669&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290113 SynlettDOI: 10.1055/s-0031-1290113AbstractAn enantioselective protonation of transient enolate generated in sulfa-Michael addition was investigated. Various α-substituted acrylic derivatives and thiols were examined as substrates. α-Benzyl acrylimide gave the best results in terms of chemical yield and enantioselectivity (up to 93% yield and 92% ee)[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5500669 Tue, 13 Dec 2011 05:00:00 +0100 5500669 Recent Developments in Asymmetric Coupling of Enolates http://www.medworm.com/index.php?rid=5500668&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290111 SynlettDOI: 10.1055/s-0031-1290111AbstractRecent progress in transition-metal-catalyzed, asymmetric couplings of carbonyl compounds is summarized. Particular emphasis is placed on the intermolecular processes that form tertiary stereocenters, which was a challenging problem for many years.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5500668 Tue, 13 Dec 2011 05:00:00 +0100 5500668 The Chemistry of α,β-Ditosyloxy Ketones: A New and Convenient Route to 4,5-Diarylisoxazoles from α,β-Chalcone Ditosylates http://www.medworm.com/index.php?rid=5500667&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290109 SynlettDOI: 10.1055/s-0031-1290109AbstractThe reaction of α,β-chalcone ditosylates with hydroxyl­amine hydrochloride under suitable conditions leads to a 1,2-aryl shift, thereby providing a new route to 4,5-disubstituted isoxazoles.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5500667 Tue, 13 Dec 2011 05:00:00 +0100 5500667 Catalytic Asymmetric Cycloaddition Reaction of Alkenyl Trichloroacetates with Nitrones http://www.medworm.com/index.php?rid=5492280&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290094 SynlettDOI: 10.1055/s-0031-1290094AbstractA catalytic enantioselective cycloaddition reaction of alkenyl trichloroacetates with nitrones was achieved using an (S)-BINOL-derived chiral tin dibromide possessing a 4-trifluoromethylphenyl group at 3- and 3′-positions as the chiral precatalyst in the presence of sodium ethoxide, sodium iodide, and ethanol. Optically active isoxazolidines with up to 95% ee were diastereoselectively obtained in high yields even from aliphatic aldehyde derived nitrones under the influence of the in situ generated chiral tin ethoxide iodide.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492280 Fri, 09 Dec 2011 05:00:00 +0100 5492280 Recent Advances in Transition-Metal-Catalyzed Esterification http://www.medworm.com/index.php?rid=5492279&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290101 SynlettDOI: 10.1055/s-0031-1290101AbstractIn this account, we summarized our recent progress in transition-metal-catalyzed esterification via different pathways, including lactonization, Chan-Lam reaction, oxidative esterification and C-H functionalization.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492279 Fri, 09 Dec 2011 05:00:00 +0100 5492279 Efficient Synthesis of the C1-C13 Fragment of Bistramide A http://www.medworm.com/index.php?rid=5492277&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290097 SynlettDOI: 10.1055/s-0031-1290097AbstractHerein we report an efficient synthesis of the C1-C13 fragment of bistramide A from (S)-1,2,4-butanetriol and Roche ester in 14 steps and 13% overall yield.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492277 Fri, 09 Dec 2011 05:00:00 +0100 5492277 Transesterification of α-Amino Esters Catalyzed by a Tetranuclear Zinc Cluster: Zn4(OCOCF3)6O http://www.medworm.com/index.php?rid=5492276&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290096 SynlettDOI: 10.1055/s-0031-1290096AbstractTransesterification of amino acid ester derivatives was developed using a tetranuclear zinc cluster, Zn4(OCOCF3)6O, as the catalyst. Because the reaction conditions were very mild, a variety of N-protective groups and functional groups on side chains were tolerated.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492276 Fri, 09 Dec 2011 05:00:00 +0100 5492276 Application of Organic Azides for the Synthesis of Nitrogen-Containing Molecules http://www.medworm.com/index.php?rid=5492275&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290108 SynlettDOI: 10.1055/s-0031-1290108AbstractIn this account, recent advances made on the reactions of several types of organic azides, such as vinyl azides, cyclic 2-azido alcohols, α-azido carbonyl compounds, towards the synthesis of ­nitrogen-containing molecules are described.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492275 Fri, 09 Dec 2011 05:00:00 +0100 5492275 An Enantiospecific Formal Total Synthesis of the 5-8-5 Tricyclic Diterpene ent-Fusicoauritone http://www.medworm.com/index.php?rid=5492274&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290095 SynlettDOI: 10.1055/s-0031-1290095AbstractAn enantiospecific formal total synthesis of the 5-8-5 tricyclic diterpene fusicoauritone has been accomplished, starting from 5-isopropyl-2-methylcyclopent-1-enemethanol [available in three steps from (R)-dihydrolimonene] employing two ring-closing-metathesis reactions for the construction of the eight- and five-membered rings.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492274 Fri, 09 Dec 2011 05:00:00 +0100 5492274 The Wieland-Miescher Ketone: A Journey from Organocatalysis to Natural Product Synthesis http://www.medworm.com/index.php?rid=5492273&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290107 SynlettDOI: 10.1055/s-0031-1290107AbstractThe Hajos-Parrish-Eder-Sauer-Wiechert reaction can be considered as the origin of asymmetric organocatalysis, giving rise to the Wieland-Miescher ketone 1 (WMK), a versatile building block. Although 40 years have passed since its discovery, a highly enantioselective and scalable synthesis of the WMK has remained elusive. This account details a solution to that problem that came about in the development of methodology towards C-8a WMK analogues as part of the total synthesis of complex diterpene natural products. The work has been placed in the context of the historical background and reactivity of this important building block, highlighting the challenges faced by organocatalysis in large-scale reactions.[...]© Georg Thieme Verlag Stuttgart Ë™ New... Synlett journals http://www.medworm.com/rss/comments.php?id=5492273 Fri, 09 Dec 2011 05:00:00 +0100 5492273 Highly Effective Recyclable Palladium-Catalyzed Ligand-Free Heck Reactions under Aerobic Conditions http://www.medworm.com/index.php?rid=5492272&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290099 SynlettDOI: 10.1055/s-0031-1290099AbstractAn effective protocol was developed for the Heck coupling reactions between various aryl halides and olefins. In the presence of 2 mol% of Pd(OAc)2, the desired products could be obtained in good yields under ligand-free and aerobic conditions. The catalytic system could be easily recycled for five times with high efficiency.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492272 Fri, 09 Dec 2011 05:00:00 +0100 5492272 A Mild Method for the Cleavage of the 4-Picolyloxy Group with Magnesium under Neutral Conditions http://www.medworm.com/index.php?rid=5492271&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290092 SynlettDOI: 10.1055/s-0031-1290092AbstractA mild and efficient method for the selective hydrolysis of 4-picolyl esters with magnesium in methanol or water in the presence of other esters and sensitive protecting groups is described. 4-Picolyl aryl ethers and thioethers are also smoothly deprotected to give the corresponding phenols and thiophenols.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492271 Fri, 09 Dec 2011 05:00:00 +0100 5492271 Indium(III) Chloride Catalyzed Convergent, Regioselective Synthesis of Annulated Quinoline and Pyridine Derivatives http://www.medworm.com/index.php?rid=5492269&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290100 SynlettDOI: 10.1055/s-0031-1290100AbstractA direct convergent two-component regioselective synthesis of annulated pyridine motif from 1-aminopenta-1,4-diene fragment and aromatic aldehyde by indium(III) chloride catalyzed reaction has been developed through a concerted pathway. A series of potentially bioactive pyranoquinoline, phenanthroline, and pyridopyrimidine derivatives has been synthesized in high yields by this protocol.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492269 Fri, 09 Dec 2011 05:00:00 +0100 5492269 An Expedient Route to 3-Methoxy-2-furaldehyde http://www.medworm.com/index.php?rid=5492267&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290103 SynlettDOI: 10.1055/s-0031-1290103AbstractAn expedient route to 3-methoxy-2-furaldehyde is presented.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492267 Fri, 09 Dec 2011 05:00:00 +0100 5492267 Towards the Total Synthesis of Thuggacin A: Synthesis of the C13-C25 Fragment Bearing All-syn Stereocenters http://www.medworm.com/index.php?rid=5492266&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290106 SynlettDOI: 10.1055/s-0031-1290106AbstractThe diastereoselective synthesis of the key C13-C25 fragment of thuggacin A is described. Two Evans aldolization steps and a diastereoselective addition of an allenylstannane control the required all-syn configuration of the five contiguous stereocenters.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492266 Fri, 09 Dec 2011 05:00:00 +0100 5492266 One-Pot Three-Component Synthesis of 4(3H)-Quinazolinones from Benzyl Halides, Isatoic Anhydride, and Primary Amines http://www.medworm.com/index.php?rid=5492278&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290098 SynlettDOI: 10.1055/s-0031-1290098AbstractA novel, one-pot, and three-component synthesis of 4(3H)-quinazolinones is described. Benzyl halides are oxidized to aldehydes under mild Kornblum conditions then undergo a three-component reaction with isatoic anhydride and primary amines to produce 4(3H)-quinazolinones in excellent yields.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492278 Wed, 07 Dec 2011 05:00:00 +0100 5492278 Facile N-Urethane-Protected α-Amino/Peptide Thioacid Preparation Using EDC and Na2S http://www.medworm.com/index.php?rid=5492270&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290091 We report herein an efficient protocol for the synthesis of N-urethane-protected α-amino/peptide thioacids from their corresponding acids mediated by EDC and Na2S. The fast reaction under mild conditions enabled the process to be completed in shorter duration with good yield circumventing column purification. The chemistry is compatible with a wide variety of urethane protecting groups, side-chain functionalities, and sterically hindered amino ­acids.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492270 Wed, 07 Dec 2011 05:00:00 +0100 5492270 SmI2-Mediated Carbonyl-Alkene Couplings for the Synthesis of Small Carbocyclic Rings http://www.medworm.com/index.php?rid=5492268&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290093 SynlettDOI: 10.1055/s-0031-1290093AbstractThe electron transfer reducing agent samarium diiodide (SmI2) mediates reductive carbonyl-alkene couplings to give small carbocyclic rings with high diastereocontrol. The substrate scope and mechanism of the reactions is discussed. The application of these versatile reactions in target synthesis is also described.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5492268 Wed, 07 Dec 2011 05:00:00 +0100 5492268 Concise Formal Synthesis of (+)-Englerin A and Total Synthesis of (-)-Orientalol F: Establishment of the Stereochemistry of the Organocatalytic [4+3]-Cycloaddition Reaction http://www.medworm.com/index.php?rid=5482572&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290090 SynlettDOI: 10.1055/s-0031-1290090AbstractThe enantioselective formal synthesis of (+)-englerin A and the total synthesis of (-)-orientalol F were successfully accomplished via a triene. The success enabled establishment of the relative as well as absolute stereochemistry of the organocatalytic [4+3]-cycloaddition reaction.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5482572 Mon, 05 Dec 2011 05:00:00 +0100 5482572 Synthesis of Imidazolidine-2-(thi)ones via C2-Selective Oxidation and Thionation of 2-Imidazolinium Halides http://www.medworm.com/index.php?rid=5482571&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290087 This article describes a scope study for the synthesis of imidazolidine-2-(thi)ones by selective oxidation or thionation of 2-imidazolinium halides, which in turn are synthesized by alkylation of 2-imidazolines obtained from an initial multicomponent reaction.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5482571 Mon, 05 Dec 2011 05:00:00 +0100 5482571 One-Step Synthesis of 3-Thioacetylsulfolane http://www.medworm.com/index.php?rid=5482570&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290089 SynlettDOI: 10.1055/s-0031-1290089AbstractA one-step synthesis of (S)-3-thioacetylsulfolane is described. Reaction of 3-sulfolene with thiolacetic acid in the presence of AIBN or Ph3SiSH under basic conditions gave racemic 3-thioacetylsulfolane in 30-32% yield. Enantiomerically pure (S)-3-thioacetylsulfolane was obtained by chiral chromatography.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5482570 Mon, 05 Dec 2011 05:00:00 +0100 5482570 Silver-Catalyzed 2-Pyridyl Arylation of Pyridine N-Oxides with Arylboronic Acids at Room Temperature http://www.medworm.com/index.php?rid=5482569&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290088 SynlettDOI: 10.1055/s-0031-1290088AbstractA novel direct arylation of pyridine N-oxides with arylboronic acids through C-H functionalization has been developed. This new reaction is performed at room temperature using catalytic silver(I) nitrate in the presence of potassium persulfate and give 2-pyridyl arylation derivatives of pyridine N-oxides.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5482569 Mon, 05 Dec 2011 05:00:00 +0100 5482569 Silver Carbonate http://www.medworm.com/index.php?rid=5464705&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290086 SynlettDOI: 10.1055/s-0031-1290086© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5464705 Tue, 29 Nov 2011 05:00:00 +0100 5464705 Direct Carbon-Carbon Bond Formation from Alcohols and Active Methylenes using NaHSO4/SiO2 http://www.medworm.com/index.php?rid=5453791&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290083 SynlettDOI: 10.1055/s-0031-1290083AbstractA simple and efficient procedure for carbon-carbon bond formation has been developed starting from alcohols and ­active methylene-containing compounds using silica gel supported sodium hydrogen sulfate (NaHSO4/SiO2) under mild conditions. NaHSO4/SiO2 can be reused without loss of catalytic activity at least ten times.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5453791 Mon, 28 Nov 2011 05:00:00 +0100 5453791 4-Chloro-3-iodoquinoline as a Synthon in the Development of New Syntheses of 1,2-Disubstituted 1H-Pyrrolo[3,2-c]quinolines http://www.medworm.com/index.php?rid=5453790&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289909 SynlettDOI: 10.1055/s-0031-1289909AbstractNew syntheses of novel 1,2-pyrrolo[3,2-c]quinolines were established using 4-chloro-3-iodoquinoline as a synthon. The approach involved a palladium-catalyzed Sonogashira reaction of 4-chloro-3-iodoquinoline with appropriate arylacetylenes, followed by nucleophilic displacement of chlorine and cyclization. Studies on the reaction of 4-chloroquinoline derivatives with sodium azide led to the unexpected 4-aminoquinolines.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5453790 Mon, 28 Nov 2011 05:00:00 +0100 5453790 Total Synthesis of Danshenspiroketallactone http://www.medworm.com/index.php?rid=5453789&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290082 SynlettDOI: 10.1055/s-0031-1290082AbstractDescribed herein is the first synthesis of the monobenz­annulated 5,5-spiroketals danshenspiroketallactone and epi-danshen­spiroketallactone, two components of the traditional Chinese medicine Danshen. Key features of the synthesis include a directed metallation-lactonisation sequence to install the isobenzofuranone moiety and an oxidative radical cyclisation to afford the monobenz­annulated 5,5-spiroketal.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5453789 Mon, 28 Nov 2011 05:00:00 +0100 5453789 Synthesis of Complex Glycosylated Carboranes for BNCT http://www.medworm.com/index.php?rid=5453788&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289910 SynlettDOI: 10.1055/s-0031-1289910AbstractAn efficient strategy for the preparation of carboranyl derivatives from a common intermediate containing a sugar moiety functionalized with an azido group is described. Such compounds should allow either the conjugation with peptides or proteins for an improved delivery of the products, or the monitoring of the biodistribution profile.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5453788 Mon, 28 Nov 2011 05:00:00 +0100 5453788 BF3×OEt2-Catalyzed Unusual Formation of cis-2,3-Disubstituted [nl]Tetrahydrofuran Scaffolds http://www.medworm.com/index.php?rid=5453787&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290084 SynlettDOI: 10.1055/s-0031-1290084AbstractAldehydes undergo smooth cyclization with 4-(phenylthio)but-3-en-1-ol in the presence of BF3Ë™OEt2 in dichloromethane at room temperature to afford a novel class of 2,3-disubstitued tetrahydrofurans in good yields with all-cis-selectivity. This method is simple, selective, and convenient for the synthesis of tetrahydrofuran scaffolds in a single step.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5453787 Mon, 28 Nov 2011 05:00:00 +0100 5453787 Regiospecific Synthesis of 3,4-Dihydrocoumarins via Substrate-Controlled [1,3]- or [3,3]-Sigmatropic Rearrangement http://www.medworm.com/index.php?rid=5453786&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289908 SynlettDOI: 10.1055/s-0031-1289908AbstractA regiospecific synthesis of 3,4-dihydrocoumarin derivatives has been achieved involving tandem rearrangement-cyclization of (E)-2-(aryloxymethyl)alk-2-enoates catalyzed by a Pd/Cu bimetallic system. Unexpected substrate-controlled [1,3]- or [3,3]-sigmatropic rearrangement was observed in the transformations.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5453786 Mon, 28 Nov 2011 05:00:00 +0100 5453786 Bis(trifluoromethanesulfonyl)imide http://www.medworm.com/index.php?rid=5453785&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1290085 SynlettDOI: 10.1055/s-0031-1290085© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5453785 Mon, 28 Nov 2011 05:00:00 +0100 5453785 Recent Advances in Selective Reactions Promoted by Barium Reagents http://www.medworm.com/index.php?rid=5447170&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289905 SynlettDOI: 10.1055/s-0031-1289905AbstractSince the first report in 1991 of the regio- and stereoselective allylation of carbonyl compounds with allylic barium reagents, various barium reagents have been utilized in organic transformations. This account focuses on recent examples of barium reagent promoted regio- and stereoselective reactions, such as ­Barbier-type propargylations, a Reformatsky-type reaction, ­Michael additions, aldol reactions, Mannich-type reactions, a Friedel-Crafts-type alkylation, and a Diels-Alder-type reaction.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447170 Wed, 23 Nov 2011 05:00:00 +0100 5447170 Concise Diverted Total Synthesis of Amphidinolide T1 and T4 from a (12E)-Cycloalkene by Selective Functionalization of the C12-C13 Double Bond http://www.medworm.com/index.php?rid=5447169&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289903 SynlettDOI: 10.1055/s-0031-1289903AbstractStarting from a 19-membered (12E)-cycloalkene prepared by ring-closing metathesis, amphidinolide T1 and T4 were ­efficiently synthesized via a short sequence of selective functionalization. The key steps highlighted stereoselective dihydroxylation of the (E)-C12-C13 double bond and highly regioselective silylation/desilylation of the (12S,13S)-diol. In particular, a significant solvent effect was discovered for suppressing 1,4 O→O silyl migration or disilylation during selective mono-silylation of the (12R,13R)- and (12S,13S)-diols in toluene. In combination with our previous synthesis of amphidinolide T3, the same (12E)-cycloal­kene serves as an advanced common intermediate for concise diverted total synthesis of amphidinolide T family of mari... Synlett journals http://www.medworm.com/rss/comments.php?id=5447169 Wed, 23 Nov 2011 05:00:00 +0100 5447169 A Metal-Free Oxidative Amination of Benzoxazoles with Primary Amines and Ammonia http://www.medworm.com/index.php?rid=5447168&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289902 SynlettDOI: 10.1055/s-0031-1289902AbstractAn efficient synthesis of 2-aminobenzoxazoles is described by a direct oxidative amination of unfunctionalized benzoxazoles with primary amines. The reaction could be performed in the absence of transition metals by using catalytic amounts of a quaternary ammonium iodide and tert-butylhydroperoxide as a cheap and easy-to-handle co-oxidant. In addition to primary amines, aqueous solutions of NH3 were used to introduce a primary amine group into the heterocyclic core.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447168 Wed, 23 Nov 2011 05:00:00 +0100 5447168 An Eficient One-Pot Synthesis of Macrocyclic Compounds Possessing Propargylamine Skeletons via Mannich Reaction http://www.medworm.com/index.php?rid=5447167&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289904 SynlettDOI: 10.1055/s-0031-1289904AbstractA new efficient method using the Mannich three-component reaction in one pot to synthesize [1+2+1]- and [2+4+2]-macrocyclic compounds possessing a propargylamine backbone was reported. Interestingly, 1,4-diazepane as a multiuse reagent played the part of a substrate to participate in the Mannich reaction and acted as a base to promote the Eglinton-Glaser dimerizations in the coordination processes simultaneously via a one-pot procedure. The target macrocycles were obtained in good yields.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447167 Wed, 23 Nov 2011 05:00:00 +0100 5447167 Synthetic Studies toward 3-(Acylamino)-1H-indazoles and Development of a One-Pot, Microwave-Assisted, Oxadiazole Condensation/Boulton-Katritzky Rearrangement http://www.medworm.com/index.php?rid=5447166&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289893 SynlettDOI: 10.1055/s-0031-1289893AbstractStudies on the Boulton-Katritzky rearrangement of 3-(2-aminoaryl)-1,2,4-oxadiazoles have led to the identification of additional electronic factors that govern the rearrangement as well as a competitive thermal rearrangement pathway for select substrates. To circumvent the limitations of the conventional thermal conversion sequence an improved protocol that employs microwave irradiation has been devised that allows access to rearrangement products in good to excellent isolated yields. Furthermore, we have developed a two-component, one-pot sequence using a microwave-assisted oxadiazole condensation/Boulton-Katritzky rearrangement to deliver 3-(acylamino)-1H-indazoles from simple esters and 2-amino-N-hydroxy-benzamidine[...]© Georg Thieme Verlag St... Synlett journals http://www.medworm.com/rss/comments.php?id=5447166 Wed, 23 Nov 2011 05:00:00 +0100 5447166 Asymmetric Inverse-Electron-Demand Hetero-Diels-Alder Reaction via Enamine-Metal Lewis Acid Bifunctional Catalysis http://www.medworm.com/index.php?rid=5447165&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289892 SynlettDOI: 10.1055/s-0031-1289892AbstractThis paper describes the development of an efficient and atom-economic asymmetric inverse-electron-demand hetero-­Diels-Alder reaction of six-membered ketones with β,γ-unsaturated α-keto esters via enamine-metal Lewis acid bifunctional catalysis.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447165 Wed, 23 Nov 2011 05:00:00 +0100 5447165 Metal-Free Relay Oxidation: Valuable Synthesis of Acylsilane and Ketones under Aerobic Oxidation http://www.medworm.com/index.php?rid=5447164&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289907 SynlettDOI: 10.1055/s-0031-1289907AbstractIn this letter, an example of interesting metal-free relay air oxidation of α-hydroxysilanes, promoted by the hydroperoxidated carbonyl compounds derived from the Michael reaction of 5,5-dimethylcyclohexane-1,3-dione and chalcone, is reported. A series of aromatic acylsilanes with TBDPS were obtained in promising isolated yields. In addition, as an extension of the relay oxidation under aerobic conditions, this catalyst-free relay oxidation induced by diketone can be applied to the oxidation of general aromatic alcohols (up to 75% yield).[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447164 Wed, 23 Nov 2011 05:00:00 +0100 5447164 Promotion of Asymmetric Aza-Claisen Rearrangement of N-Allylic Carboxamides Using Excess Base http://www.medworm.com/index.php?rid=5447163&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289899 SynlettDOI: 10.1055/s-0031-1289899AbstractThe aza-Claisen rearrangement of the enolate of N-(Z)-crotyl-N-(S)-phenethylpropanamide did not proceed in the presence of 1.5 equivalents of LHMDS as a base. However, the use of a large excess of base (10 equiv) promoted the reaction to give N-(S)-phenethyl-anti-2,3-dimethylpent-4-enamide with good stereoselectivities (anti/syn = ca. 95:5). An excess of base stabilized the amide enolates and prevented the decomposition to the ketene to prompt the rearrangement of various carboxamides with good stereoselectivity. This reaction provided a new method for the construction of asymmetric quaternary carbon centers.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Syn... Synlett journals http://www.medworm.com/rss/comments.php?id=5447163 Wed, 23 Nov 2011 05:00:00 +0100 5447163 [MeC(OH)2]+ClO4-: A New Efficient Organocatalyst for the Preparation of 1-Amido- and 1-Carbamato-alkyl Naphthols http://www.medworm.com/index.php?rid=5447162&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289906 SynlettDOI: 10.1055/s-0031-1289906Abstract[MeC(OH)2]+ClO4- as a super acidic ionic liquid is found to be a new and highly efficient catalyst in the synthesis of amidoalkyl naphthols via three-component condensation of β-naphthol and aldehydes with nitriles, amides, or carbamates.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447162 Wed, 23 Nov 2011 05:00:00 +0100 5447162 A Pictet-Spengler Cyclisation Methodology for the Construction of Nonproteinogenic Tetrahydroisoquinoline Quaternary Amino Acids http://www.medworm.com/index.php?rid=5447161&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289901 SynlettDOI: 10.1055/s-0031-1289901AbstractA simple highly stereoselective route to tetrahydroisoquinoline quaternary amino acids from phenylalanine is described.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447161 Wed, 23 Nov 2011 05:00:00 +0100 5447161 Fused Polycyclic Aromatic Compounds with Near Infrared Absorption and Emission http://www.medworm.com/index.php?rid=5447160&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289894 SynlettDOI: 10.1055/s-0031-1289894AbstractIn this account, we provide an overview of our own efforts in the exploration of fused polycyclic aromatic compounds with NIR absorption and emission.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447160 Wed, 23 Nov 2011 05:00:00 +0100 5447160 Reactions of Nitroalkenes with Nitroalkanes or Sulfur Ylides Catalyzed by Amine-Thiourea Bifunctional Polymeric Organocatalysts http://www.medworm.com/index.php?rid=5447159&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289900 SynlettDOI: 10.1055/s-0031-1289900AbstractNon-cross-linked and cross-linked bifunctional polystyrenes bearing both amine and thiourea groups have been synthesized and used as organocatalysts in reactions between nitroalkenes and nitroalkanes or sulfur ylides. Control experiments using monofunctional polymers with only either amine or thiourea groups attached indicated that both functional groups were essential for efficient catalysis of the reactions studied. The non-cross-linked polystyrene was soluble in typical organic solvents and was used as a homogeneous catalyst, while the cross-linked polystyrene was used as a heterogeneous catalyst.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447159 Wed, 23 Nov 2011 05:00:00 +0100 5447159 Synthesis of the C1-C13 Fragment of Biselyngbyaside http://www.medworm.com/index.php?rid=5447158&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289898 SynlettDOI: 10.1055/s-0031-1289898AbstractAn advanced intermediate vinyl iodide corresponding to the C1-C13 fragment of the macrolide biselyngbyaside was prepared by a cross-metathesis reaction between vinyl alcohol and ­alkene building blocks. The latter fragment, containing two stereocenters, was obtained by employing an asymmetric alkylation, a Wittig reaction, a hydrozirconation, and a Brown allylation as key steps.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5447158 Wed, 23 Nov 2011 05:00:00 +0100 5447158 In Situ Generation of Palladium Nanoparticles: Reusable, Ligand-Free Heck Reaction in PEG-400 Assisted by Focused Microwave Irradiation http://www.medworm.com/index.php?rid=5436920&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289897 Synlett 2011; 2011: 2905-2905DOI: 10.1055/s-0031-1289897© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5436920 Tue, 22 Nov 2011 05:00:00 +0100 5436920 Synthesis of Aminoindolizine and Quinoline Derivatives via Fe(acac)3/TBAOH-Catalyzed Sequential Cross-Coupling-Cycloisomerization Reactions http://www.medworm.com/index.php?rid=5436919&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0030-1289896 Synlett 2011; 2011: 2906-2906DOI: 10.1055/s-0030-1289896© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5436919 Tue, 22 Nov 2011 05:00:00 +0100 5436919 A Highly Sustainable and Active Catalyst for Suzuki-Miyaura Reaction: [nl]Palladium-Supported Ionic Liquid Catalyst (SILC) Coated with Polymer http://www.medworm.com/index.php?rid=5436918&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289895 Synlett 2011; 2011: 2905-2905DOI: 10.1055/s-0031-1289895© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5436918 Tue, 22 Nov 2011 05:00:00 +0100 5436918 Synform issue 2011/12 http://www.medworm.com/index.php?rid=5436917&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289432 Synlett 2011; 2011: A109-A118DOI: 10.1055/s-0031-1289432© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.Article in Thieme eJournals:Table of contents (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5436917 Tue, 22 Nov 2011 05:00:00 +0100 5436917 Easy Access to (E)-β-Ocimene http://www.medworm.com/index.php?rid=5416902&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289869 SynlettDOI: 10.1055/s-0031-1289869Abstractβ-Ocimene is one of the most common monoterpenes found in Nature, but a simple and reliable synthesis of the pure E-isomer has been missing. Here, we report a simple procedure involving a Grignard coupling as the key step that allows its synthesis on gram scales. The configuration of the double bond is fixed in the starting material.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416902 Mon, 14 Nov 2011 05:00:00 +0100 5416902 Gold-Catalyzed Cycloisomerization of Functionalized 1,5-Enynes - An Entry to Polycyclic Framework http://www.medworm.com/index.php?rid=5416921&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289867 SynlettDOI: 10.1055/s-0031-1289867AbstractThe gold-catalyzed cycloisomerization reactions of variously functionalized 1,5-enynes are presented. The cyclization processes implying aryl- and 1,3-dicarbonyl-substituted skeletons are conducted under mild conditions and lead to cyclic structures obtained according to 6-endo-dig or 5-endo-dig mode depending on the involved nucleophilic partner. Some competitive pathways and trapping of carbocationic intermediates are highlighted.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416921 Fri, 11 Nov 2011 05:00:00 +0100 5416921 Iron-Mediated Cyanation of Methoxybenzene, Indole, and 2-Arylpyridine C-H Bonds http://www.medworm.com/index.php?rid=5416920&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289883 SynlettDOI: 10.1055/s-0031-1289883AbstractAn iron-mediated direct cyanation of indole and 2-arylpyridine C-H bonds is described. Notably, trimethoxybenzene reacted smoothly under the procedure, forming a C-CN bond via C-H bond cleavage without chelation assistance.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416920 Fri, 11 Nov 2011 05:00:00 +0100 5416920 A Practical Synthesis of [(1S,3S)-3-Aminocyclohexyl]methanol and 2-[(1S,3S)-3-Aminocyclohexyl]propan-2-ol, Useful Intermediates for the Preparation of Novel mPGES-1 Inhibitors http://www.medworm.com/index.php?rid=5416919&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289884 SynlettDOI: 10.1055/s-0031-1289884AbstractMicrosomal prostaglandin E2 synthase-1 (mPGES-1) is a novel therapeutic target for the treatment of inflammation and pain. During the course of studies aimed at the identification of a suitable mPGES-1 inhibitor for clinical development, a need arose for preparing enantiomerically enriched amino alcohols (S,S)-2 and (S,S)-3. Described herein, a concise synthesis of (S,S)-2 and (S,S)-3 has been developed wherein both amino alcohols are derived from a commercially available, low-cost starting material.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416919 Fri, 11 Nov 2011 05:00:00 +0100 5416919 Enantioselective Intramolecular Hydroamination of N-Alkenyl Ureas Catalyzed by tropos BIPHEP-Gold(I) Complexes with Au-Au Interaction http://www.medworm.com/index.php?rid=5416918&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289875 SynlettDOI: 10.1055/s-0031-1289875AbstractDinuclear gold complexes significantly accelerate intramolecular hydroamination of N-alkenyl ureas via proximal and bimetallic activation of alkene and urea. Tropos BIPHEP-gold complexes having Au-Au interaction affords higher enantioselectivity than the BINAP-gold counterparts without Au-Au interaction.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416918 Fri, 11 Nov 2011 05:00:00 +0100 5416918 Catalytic Oxidative Cleavage of 1,3-Diketones to Carboxylic Acids by Aerobic Photooxidation with Iodine http://www.medworm.com/index.php?rid=5416917&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289891 We report the catalytic oxidative cleavage of 1,3-diketones to the corresponding carboxylic acids by aerobic photooxidation with iodine under irradiation with a high-pressure mercury lamp.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416917 Fri, 11 Nov 2011 05:00:00 +0100 5416917 Synthesis of an Advanced Intermediate of the Macrotricyclic Core of Roseophilin http://www.medworm.com/index.php?rid=5416916&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289882 SynlettDOI: 10.1055/s-0031-1289882AbstractA facile approach for the preparation of a cyclopenta[b]pyrrole derivative, the key precursor in Frontier’s synthesis of the macrotricyclic core of roseophilin, was developed. The key steps involved two successive pyrrole acylations and a Sc(OTf)3-catalyzed Nazarov cyclization reaction.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416916 Fri, 11 Nov 2011 05:00:00 +0100 5416916 Palladium-Catalyzed Aromatic Sulfonylation: A New Catalytic Domino Process Exploiting in situ Generated Sulfinate Anions http://www.medworm.com/index.php?rid=5416915&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289880 SynlettDOI: 10.1055/s-0031-1289880AbstractAllylic sulfones are excellent precursors of aryl sulfones via a new Pd-catalyzed domino sequence involving in situ generation of sulfinate anions and subsequent cross-coupling with aryl ­iodides or bromides.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416915 Fri, 11 Nov 2011 05:00:00 +0100 5416915 Enantio- and Diastereoselective Nitro-Mannich Reactions with in situ Generated N-Boc-imines Catalyzed by a Bifunctional Thiourea-Guanidine Catalyst http://www.medworm.com/index.php?rid=5416914&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289885 SynlettDOI: 10.1055/s-0031-1289885AbstractThe asymmetric nitro-Mannich reactions of nitroalkanes and in situ generated N-Boc-imines were achieved with a new type of thiourea-guanidine bifunctional organocatalyst. The novel transformations exhibited good diastereoselectivities, and the adducts bearing adjacent chiral centers were generally obtained in moderate to high enantioselectivities (up to 94% ee). This reaction provides a concise and alternative route converting readily accessible and stable N-carbamate amido sulfones into optically active 1,2-diamino compounds.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416914 Fri, 11 Nov 2011 05:00:00 +0100 5416914 Facile Synthesis of 5-Carboxamide-oxazolines via a Passerini 3CC-Staudinger-aza-Wittig Sequence http://www.medworm.com/index.php?rid=5416913&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289865 SynlettDOI: 10.1055/s-0031-1289865Abstract5-Carboxamide-oxazolines were synthesized via a Passerini 3CC-Staudinger-aza-Wittig sequence in moderate to good yields, starting from easily accessible chloroacetaldehyde, isocyanides, and various acids.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416913 Fri, 11 Nov 2011 05:00:00 +0100 5416913 Aqueous-Phase Heck Coupling of 5-Iodouridine and Alkenes under Phosphine-Free Conditions http://www.medworm.com/index.php?rid=5416912&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289886 SynlettDOI: 10.1055/s-0031-1289886AbstractPalladium-catalyzed Heck couplings between 5-iodouridine and alkenes were carried out in aqueous media in the presence of triethylamine under phosphine-free conditions to give the desired products in high yields. In the absence of phosphine ligand, triethyl­amine appears to play a critical role in both generating the active catalyst species and serving as the base in the reaction.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416912 Fri, 11 Nov 2011 05:00:00 +0100 5416912 An Efficient Copper-Catalyzed One-Pot Synthesis of Diaryl Thioethers by Coupling of Arylboronic Acids with Potassium Ethyl Xanthogenate under Mild Conditions http://www.medworm.com/index.php?rid=5416911&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289874 SynlettDOI: 10.1055/s-0031-1289874AbstractA simple and environmentally benign one-pot synthesis of diaryl thioethers by coupling of arylboronic acids with potassium ethyl xanthogenate through a double arylation process has been developed. The aryl thiols were generated in situ, and the reactions proceeded smoothly to give the corresponding products in good to excellent yields under very mild conditions.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416911 Fri, 11 Nov 2011 05:00:00 +0100 5416911 Synthesis of a Chiral Key Intermediate of Neurokinin Antagonist SSR 240600 by Asymmetric Allylic Alkylation http://www.medworm.com/index.php?rid=5416910&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289878 SynlettDOI: 10.1055/s-0031-1289878AbstractThe preparation of optically active morpholine-2-aryl-2-acetaldehyde from morpholine-2-aryl-3-one is reported. The quaternary carbon is introduced during a palladium-promoted asymmetric allylic alkylation. This is a useful intermediate in the synthesis and development of potent NK antagonist.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416910 Fri, 11 Nov 2011 05:00:00 +0100 5416910 Stereoselective Total Synthesis of (-)-Isocladospolide B and Cladospolide B and C http://www.medworm.com/index.php?rid=5416909&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289868 SynlettDOI: 10.1055/s-0031-1289868AbstractThe enantioselective synthesis of bioactive butenolides isocladospolide B, cladospolide B, and cladospolide-C has been achieved from (S)-propylene oxide. Of the three stereogenic centers, the C-4/C-5 vic-diol was obtained using diastereo- and enantio­selective Brown hydroxycrotylation, while the C-11 stereocenter was created by Jacobsen hydrolytic kinetic resolution.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416909 Fri, 11 Nov 2011 05:00:00 +0100 5416909 Stereoselective γ-Olefination of Substituted Cyclobutenediones by Organocatalysis http://www.medworm.com/index.php?rid=5416908&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289879 SynlettDOI: 10.1055/s-0031-1289879AbstractMethods are described for the stereoselective synthesis of alkenyl-substituted cyclobutenediones from alkyl-substituted cyclobutenediones and aldehydes in 70-91% yields using pyrrolidine as catalyst under mild reaction conditions.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416908 Fri, 11 Nov 2011 05:00:00 +0100 5416908 An Efficient Copper-Catalyzed Microwave-Assisted S-Arylation towards the Synthesis of 8-Arylsulfanyl Adenines http://www.medworm.com/index.php?rid=5416907&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289888 We report a microwave-assisted synthetic protocol for the C-S cross-coupling reaction of aryl iodides and 8-mercaptoadenine using CuI and n-Bu4NBr with NaOt-Bu in DMF. The method is rapid, simple, and cost efficient, and leads in high yields to biologically relevant aryl sulfides.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416907 Fri, 11 Nov 2011 05:00:00 +0100 5416907 Towards the First Chemical Synthesis of the Hexasaccharide O-Antigen of Vibrio cholerae O139 http://www.medworm.com/index.php?rid=5416906&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289876 SynlettDOI: 10.1055/s-0031-1289876AbstractThe hexasaccharide O-antigen of Vibrio cholerae O139 was synthesized in its protected form from thioglycosides and glycosyl bromides as glycosyl donors by a stepwise and blockwise approach. The synthesis was designed to permit a global, one-step deprotection (H2, Pd/C). It allows the transformation of 15 functionalities in one operation, namely the removal of ten benzyl protecting groups, the removal of a trichloroethyl phosphate protecting group, the conversion of two N-trichloroacetyl into N-acetyl groups, a bromomethyl into a methyl group, and the conversion of an azido into an amino group.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416906 Fri, 11 Nov 2011 05:00:00 +0100 5416906 Synthesis of Dibenzofurans by Palladium-Catalysed Tandem Denitrification/C-H Activation http://www.medworm.com/index.php?rid=5416905&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289881 SynlettDOI: 10.1055/s-0031-1289881AbstractA palladium-catalysed method for intramolecular cyclisation of ortho-diazonium salts of diaryl ethers to give dibenzofurans is described. The protocol uses 3 mol% palladium acetate as the catalyst in refluxing ethanol in the absence of base.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416905 Fri, 11 Nov 2011 05:00:00 +0100 5416905 A Reactivity Switch in the Gold-Catalysed Coupling of Allyl Sulfides with Propargylic Carboxylates http://www.medworm.com/index.php?rid=5416904&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289866 SynlettDOI: 10.1055/s-0031-1289866AbstractThe gold-catalysed coupling of allyl sulfides with propargylic carboxylates follows different pathways depending upon the choice of nonmigrating group on the sulfur and the aromatic group at the propargylic position of the alkyne substrate.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416904 Fri, 11 Nov 2011 05:00:00 +0100 5416904 Construction of Enantioenriched Tertiary Stereogenic Centers by Nickel- and Palladium-Catalyzed Cross-Coupling Reactions of Alkyl Electrophiles http://www.medworm.com/index.php?rid=5416903&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289871 SynlettDOI: 10.1055/s-0031-1289871AbstractNickel and palladium catalysts have been developed for the cross-coupling of many challenging secondary alkyl electrophiles. Recent progress in this area is reviewed with emphasis on the control of stereochemistry in the formation of tertiary stereocenters. Stereoconvergent methods are discussed and recent alternative stereospecific approaches are highlighted.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416903 Fri, 11 Nov 2011 05:00:00 +0100 5416903 Hexamethylenetetramine http://www.medworm.com/index.php?rid=5416901&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289890 SynlettDOI: 10.1055/s-0031-1289890© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416901 Fri, 11 Nov 2011 05:00:00 +0100 5416901 Room-Temperature and Metal-Free Synthesis of 1,1-Dithio-1-alkenes from 1,1-Dibromo-1-alkenes and Thiols http://www.medworm.com/index.php?rid=5416900&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289872 SynlettDOI: 10.1055/s-0031-1289872AbstractAn efficient metal-free synthesis of 1,1-dithio-1-alkenes from 1,1-dibromo-1-alkenes and thiols using a diazabicycloundecene/dimethyl sulfoxide system was developed. The method was found suitable for various 1,1-dibromo-1-alkenes. The synthesis was completed within 5-15 minutes at room temperature with moderate to excellent yields.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416900 Fri, 11 Nov 2011 05:00:00 +0100 5416900 Sterically Controlled Stereoregulation in Aldol Reactions of 3-Aryl-1-alkyl Dihydrothiouracils http://www.medworm.com/index.php?rid=5416899&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289889 SynlettDOI: 10.1055/s-0031-1289889AbstractAldol reactions of 3-aryl-1-alkyl dihydrothiouracils were investigated with respect to the orientation of the exocyclic group at N1, electronic effects of the aryl substituent at N3 and the steric demands of the electrophile. The reactions highlight the preference for formation of the anti aldol diastereomer with increasing steric constraints of the reactants.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416899 Fri, 11 Nov 2011 05:00:00 +0100 5416899 Potassium tert-Butoxide http://www.medworm.com/index.php?rid=5416898&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289873 SynlettDOI: 10.1055/s-0031-1289873© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  FREE Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416898 Fri, 11 Nov 2011 05:00:00 +0100 5416898 A Highly Diastereoselective Access to Silicon-Containing Oxazines via the TMSOTf-Promoted Reactions of N-Benzoyl-N,O-acetals with Allyl Silanes http://www.medworm.com/index.php?rid=5416897&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289877 SynlettDOI: 10.1055/s-0031-1289877AbstractA TMSOTf-promoted cycloaddition of N-benzoyl-N,O-acetals with allyl silanes to synthesize silicon-containing oxazines with high diastereoselectivities has been developed. The obtained products might be useful as building blocks in organic synthesis.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5416897 Fri, 11 Nov 2011 05:00:00 +0100 5416897 A Facile and Efficient Asymmetric Synthesis of Florfenicol http://www.medworm.com/index.php?rid=5396020&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289858 SynlettDOI: 10.1055/s-0031-1289858AbstractA facile and efficient enantioselective synthesis of flor­fenicol starting from commercially available 4-methylthiobenzaldehyde is described. Key features of the synthesis include a one-step oxidation of allyl and thioether groups in allylic alcohol to form (2S,3S)-epoxide under Sharpless epoxidation conditions and a highly efficient conversion of (1R,2R)-azide into amino alcohol via debenzylation and reduction of an azido moiety in one-pot operation.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5396020 Wed, 09 Nov 2011 05:00:00 +0100 5396020 Double Arylation of Diynes and Alkynylation of Functionalized Heteroaryl Halides by a Practical Heck Reaction in an Ionic Liquid http://www.medworm.com/index.php?rid=5396019&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289861 SynlettDOI: 10.1055/s-0031-1289861AbstractThe efficient palladium-catalyzed alkynylation of electron-rich bromoheteroarenes, incorporating deactivating electron-donating methyl and methoxy groups, and the (hetero)arylation of diynes, take place in the imidazolium ionic liquid [BMIM][BF4], as a highly polar non-volatile solvent. This method may constitute a sustainable alternative to classical solvents such as dioxane, DMF, NMP, or DMAc. New enynes are formed in the presence of a system encompassing a copper-free palladium catalyst, triphenylphosphine as ligand, and various inexpensive bases. The enyne molecules reported are selectively synthesized in high yields and are mostly unprecedented.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |Â... Synlett journals http://www.medworm.com/rss/comments.php?id=5396019 Wed, 09 Nov 2011 05:00:00 +0100 5396019 Radical Addition of Silanes to Alkenes Followed by Oxidation http://www.medworm.com/index.php?rid=5396018&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289568 SynlettDOI: 10.1055/s-0031-1289568AbstractPhenyldimethylsilane and trichlorosilane are shown to undergo efficient radical hydrosilylation reactions, on reaction with various alkenes, using triethylborane as the initiator. Adducts from the trichlorosilane reactions can be oxidised to afford alcohols in good yields. This two-step process leads to the anti-Markovnikov hydration of alkenes.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5396018 Wed, 09 Nov 2011 05:00:00 +0100 5396018 Synthesis of an Advanced Intermediate toward the hNK-1 Antagonist with the Cyclopentane Core http://www.medworm.com/index.php?rid=5396017&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289863 SynlettDOI: 10.1055/s-0031-1289863AbstractAllylic substitution of monomethoxyacetate of 4-cyclopentene-1,3-diol (91% ee) with 4-FC6H4ZnBr (4 equiv) and CuCl (30 mol%) gave anti-SN2′ product, which upon epoxidation with MCPBA afforded α-epoxide stereoselectively. The epoxide was reduced with LiEt3BH, and the resulting alcohol was converted into the targeted amine by using Mitsunobu reactions twice with 3,5-(O2N)2C6H3CO2H and then with phthalimide.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5396017 Wed, 09 Nov 2011 05:00:00 +0100 5396017 Catalytic Enantioselective Arylation of Aldehydes by Using Functionalized Grignard Reagents Generated from Aryl Bromides http://www.medworm.com/index.php?rid=5396016&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289854 SynlettDOI: 10.1055/s-0031-1289854AbstractAn efficient catalytic method has been developed for the enantioselective synthesis of functionalized diarylmethanols starting from aryl bromides and aldehydes. In the presence of (R)-3-(3,5-diphenylphenyl)BINOL (2 mol%) and titanium tetraisopropoxide, functionalized aryl Grignard reagents (FGArMgCl; FG = 3-F3C, 4-F3C, 3-Br, 3-CN, 4-CN), prepared in situ by treatment of the bromides with i-PrMgClË™LiCl, undergo addition to aldehydes to give the corresponding functionalized diarylmethanols in high enantioselectivities.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5396016 Wed, 09 Nov 2011 05:00:00 +0100 5396016 Phosphomolybdic Acid Catalyzed Synthesis of 1,2,4,5-Tetraoxanes http://www.medworm.com/index.php?rid=5396015&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289864 SynlettDOI: 10.1055/s-0031-1289864Abstract1,1-Dihydroperoxides were converted into 1,2,4,5-tetraoxanes through condensation with the corresponding ketones in 36-91% yields using phosphomolybdic acid as the catalyst and anhydrous MgSO4 as the water scavenger.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5396015 Wed, 09 Nov 2011 05:00:00 +0100 5396015 Ammonium Phosphorodithioate: A Mild, Easily Handled, Efficient, and Air-Stable Reagent for the Conversion of Amides into Thioamides http://www.medworm.com/index.php?rid=5396014&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289859 SynlettDOI: 10.1055/s-0031-1289859AbstractA simple, efficient, and new method has been developed for the synthesis of thioamides from amides. As described below, the reaction of a variety of aromatic and aliphatic amides in the presence of ammonium phosphorodithioate as an efficient reagent proceeded effectively to afford the corresponding thioamides in high yields. This method is easy, rapid, and high-yielding for the synthesis of thioamides from amides using an easily handled reagent.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5396014 Wed, 09 Nov 2011 05:00:00 +0100 5396014 Iron-Catalyzed Reductive Dehydroxylation of Benzylic Alcohols Using Polymethylhydrosiloxane (PMHS) http://www.medworm.com/index.php?rid=5396013&cid=s_36628_59_f&fid=36628&url=http%3A%2F%2Fdx.doi.org%2F10.1055%2Fs-0031-1289857 SynlettDOI: 10.1055/s-0031-1289857AbstractThe combination of FeCl3 and PMHS is an efficient reducing system for the selective dehydroxylation of secondary benzylic alcohols, even in the presence of carbonyls, under very mild conditions.[...]© Georg Thieme Verlag Stuttgart Ë™ New YorkArticle in Thieme eJournals:Table of contents  |  Abstract  |  Full text (Source: Synlett) Synlett journals http://www.medworm.com/rss/comments.php?id=5396013 Wed, 09 Nov 2011 05:00:00 +0100 5396013