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Unsaturated Esters (unsaturated + ester)
Selected AbstractsAsymmetric Hydrogenation of ,,,-Unsaturated Ester- PhosphonatesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009Yange Huang Abstract The rhodium-catalyzed asymmetric hydrogenation of readily available ,,,-unsaturated ester-phosphonates affords the corresponding ,-chiral phosphonates in excellent yield and ee. The resulting products are useful multifunctional building blocks applied in the synthesis of physiologically active compounds. [source] Lewis Acid Induced [2+2] Cycloadditions of Silyl Enol Ethers with ,,,-Unsaturated Esters: A DFT AnalysisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2005Manuel Arnó Abstract The Lewis acid (LA) induced cycloaddition of trimethysilyl vinyl ether with methyl acrylate has been studied by DFT methods at the B3LYP/6-31G* level. In the absence of an LA, a [4+2] cycloaddition between the silyl enol ether and methyl acrylate in the s-cis conformation takes place through an asynchronous, concerted bond-formation process. This cycloaddition presents a large activation enthalpy of 21.1 kcal,mol,1. Coordination of the LA AlCl3 to the carbonyl oxygen atom of methyl acrylate yields a change of molecular mechanism from a concerted to a two-step mechanism and produces a drastic reduction of the activation energy. This stepwise mechanism is initialized by the nucleophilic attack of the enol ether at the ,-position of methyl acrylate in a Michael-type addition. The very low activation energy (7.1 kcal,mol,1)associated with this nucleophilic attack can be related to the increase of the electrophilicity of the LA-coordinated ,,,-unsaturated ester, which favors the cycloaddition through a polar process. The subsequent ring-closure allows the formation of the corresponding [2+2] and [4+2] cycloadducts. While the [4+2] cycloadduct is formed by kinetic control, the [2+2] cycloadducts are formed by thermodynamic control. The energetic results provide an explanation for the conversion of [4+2] cycloadducts into the thermodynamically more stable [2+2] ones. The cis/trans ratio found for the catalytic [2+2] process is in agreement with the experimental outcome. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Michael Reaction of Nitroalkanes with ,-Nitroacrylates under a Solid Promoter: Advanced Regio- and Diastereoselective Synthesis of Nitro-Functionalized ,,,-Unsaturated Esters and 1,3-Butadiene-2-carboxylatesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010Alessandro Palmieri Abstract A new class of nitro-functionalized ,,,-unsaturated esters has been prepared by a regio- and diastereoselective Michael addition of nitroalkanes to ,-nitroacrylates, performed at room temperature, under carbonate on polymer as promoter, and in the presence of ethyl acetate as eco-friendly solvent. Moreover, by the modular choice of the reaction conditions the method allows the synthesis of 1,3-butadiene-2-carboxylates. [source] Berichtigung: Palladium-Catalyzed ,-Arylation of ,,,-Unsaturated Esters from Silyl Ketene AcetalsANGEWANDTE CHEMIE, Issue 40 2010David No abstract is available for this article. [source] Palladium-Catalyzed ,-Arylation of ,,,-Unsaturated Esters from Silyl Ketene Acetals,ANGEWANDTE CHEMIE, Issue 33 2010David Smarter Katalysator: Eine Methode für die Palladium-katalysierte ,-Arylierung von ,,,-ungesättigten Estern wurde entwickelt, die über Silylketenacetale verläuft und ohne Fluorid-Aktivatoren auskommt. Die Kupplung gelingt mit elektronenreichen und elektronenarmen Aryl- und Vinylbromiden in hohen Ausbeuten, und andere funktionelle Gruppen werden gut toleriert. [source] ChemInform Abstract: Influence of the Gas Atmosphere on the Deprotection of (Z)-,-Hydroxy-,,,-Unsaturated Esters.CHEMINFORM, Issue 7 2010Irakusne Lopez Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Polymer-Assisted Solution-Phase Synthesis under Combined Ultrasound and Microwave Irradiation: Preparation of ,,,-Unsaturated Esters and Carboxylic Acids, Key Intermediates of Novel Sigma Ligands.CHEMINFORM, Issue 4 2010D. Rossi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Efficient Alkenation of Aldehydes and Ketones to ,,,-Unsaturated Esters Using ,,,-Bis(dimethylsilyl)-substituted Esters.CHEMINFORM, Issue 1 2010Katsukiyo Miura Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Organocatalytic Michael Addition of Aldehydes to ,-Keto-,,,-Unsaturated Esters.CHEMINFORM, Issue 16 2009An Efficient Entry to Versatile Chiral Building Blocks. Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: 3,5-Bis(trifluoromethyl)phenyl Sulfones for the Highly Stereoselective Julia,Kocienski Synthesis of ,,,-Unsaturated Esters and Weinreb Amides.CHEMINFORM, Issue 41 2008Diego A. Alonso Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Zinc Oxide,Tetrabutylammonium Bromide Tandem as a Highly Efficient, Green, and Reusable Catalyst for the Michael Addition of Pyrimidine and Purine Nucleobases to ,,,-Unsaturated Esters under Solvent-Free Conditions.CHEMINFORM, Issue 39 2008Abdolkarim Zare Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A New Synthesis of ,,,-Unsaturated Esters from Three Components, Aldehydes, Chloromethyl p-Tolyl Sulfoxide, and tert-Butyl Acetate, via Magnesium Carbenoid 1,2-CH and 1,2-CC Insertion as the Key Reaction.CHEMINFORM, Issue 2 2008Tsuyoshi Satoh Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Cu(I) Tol-BINAP-Catalyzed Enantioselective Michael Reactions of Grignard Reagents and Unsaturated Esters.CHEMINFORM, Issue 23 2007Shun-Yi Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Manganese-Promoted ,-Elimination Reactions: Totally Stereoselective Synthesis of (E)-,,,-Unsaturated Esters.CHEMINFORM, Issue 23 2006Jose M. Concellon Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthesis of 2-Alkylidenetetrahydrofurans by Ru-Catalyzed Regio- and Stereoselective Codimerization of Dihydrofurans with ,,,-Unsaturated Esters.CHEMINFORM, Issue 10 2006Hiroshi Tsujita Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] The Reaction of Organozinc Reagents with Trifluoroacylated Phosphonates: Synthesis of Trifluoromethylated ,,,-Unsaturated Esters with an Active Methylene Moiety.CHEMINFORM, Issue 40 2004Yanchang Shen Abstract For Abstract see ChemInform Abstract in Full Text. [source] Synthesis of Functionalized N-Arylsulfonyl Aziridines from ,,,-Unsaturated Esters, Amides, Ketones, and Nitriles Using N,N-Dichloroarylsulfonamides as Nitrogen Source.CHEMINFORM, Issue 32 2004Upender K. Nadir No abstract is available for this article. [source] Efficient and Stereoselective Synthesis of ,-Trifluoromethyl ,,,-Unsaturated Esters via Iron(III) Porphyrin-Catalyzed Olefination of Ketones.CHEMINFORM, Issue 47 2003Ying Chen No abstract is available for this article. [source] ChemInform Abstract: The Stereospecific Trifluoromethylation of ,-Iodo-,,,-Unsaturated Esters: A Novel Synthesis of (Z)-,-Trifluoromethyl-,,,-Unsaturated Esters.CHEMINFORM, Issue 28 2001Xingguo Zhang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Asymmetric Dihydroxylation of ,,,-Unsaturated Carboxylic Esterswith Trisubstituted C=C Bonds , Enantioselective Syntheses of Trisubstituted ,-ButyrolactonesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2006Tobias Kapferer Abstract ,,,-Unsaturated esters with stereodefined trisubstitued C=C double bonds were prepared by the Arndt,Eistert homologation of ,,,-unsaturated carboxyl halides, by two-step methoxycarbonylation of allylbarium reagents, by deconjugation of ,,,-unsaturated esters, and by Horner,Wadsworth,Emmons variants of the Stobbe condensation. Sharpless asymmetric dihydroxylation of the ,,,-unsaturated esters, followed by spontaneous cyclization, afforded ,-hydroxy-,-lactones in moderate to good yields and with enantiomeric excesses of up to 97,%. Similarly, tetrahydroxy-,-lactones were obtained from diunsaturated esters; these lactones were converted into a bislactone and an unsaturated ,-hydroxy ,-lactone. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] ChemInform Abstract: A Study of Conjugate Addition to a ,,,-Dioxolanyl-,,,-unsaturated Ester.CHEMINFORM, Issue 39 2001Guoxia Han Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Highly Efficient and Stereoselective Julia,Kocienski Protocol for the Synthesis of ,-Fluoro-,,,-unsaturated Esters and Weinreb Amides Employing 3,5-Bis(trifluoromethyl)phenyl (BTFP) SulfonesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2008Diego Abstract ,-Fluoroacetates 3 and Weinreb amide 4, bearing a ,-[3,5-bis(trifluoromethyl)phenyl]sulfonyl (BTFP-sulfonyl) group at the ,-position, are employed in the highly stereoselective synthesis of ,-fluoro-,,,-unsaturated alkenoates and Weinreb amides, respectively. Aromatic and aliphatic aldehydes are condensed under extremely mild and simple reaction conditions using potassium carbonate in dimethylformamide at room temperature under solid-liquid phase-transfer catalysis conditions in good yields and high Z -diastereoselectivities, specially in the case of the fluorinated Weinreb amides. A detailed computational mechanistic study suggests a final non-concerted elimination of sulfur dioxide and 3,5-bis(trifluoromethyl)phenoxide and explains the observed high stereoselectivities for the reaction on the basis of thermodynamic and kinetic considerations. [source] ChemInform Abstract: Synthesis of (E)-,-Ethynyl-,,,-unsaturated Esters (VI) from Allenyl Acetates (V) Catalyzed by DABCO and Their Application to Sonogashira Cross-Coupling Reactions.CHEMINFORM, Issue 31 2010Hyunseok Kim Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Stereoselective DABCO-Catalyzed Synthesis of (E)-,-Ethynyl-,,,-unsaturated Esters from Allenyl Acetates.CHEMINFORM, Issue 30 2009Yongsik Choe Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Tandem ,-Enamino Ester Formation and Cyclization with o-Alkynyl Anilines Catalyzed by InBr3: Efficient Synthesis of ,-(N-Indolyl)-,,,-unsaturated Esters.CHEMINFORM, Issue 24 2009Kenichi Murai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Highly Efficient and Stereoselective Julia,Kocienski Protocol for the Synthesis of ,-Fluoro-,,,-unsaturated Esters and Weinreb Amides Employing 3,5-Bis(trifluoromethyl)phenyl (BTFP) Sulfones.CHEMINFORM, Issue 50 2008Diego A. Alonso Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Highly Stereoselective Epoxidation of ,-Methyl-,-hydroxy-,,,-unsaturated Esters: Rationalization and Synthetic Applications.CHEMINFORM, Issue 1 2008Irakusne Lopez Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Intramolecular Nucleophilic Epoxidation of ,-Amino-,,,-unsaturated Esters with an N-Hydroperoxymethyl Group.CHEMINFORM, Issue 48 2005Dongwon Yoo Abstract For Abstract see ChemInform Abstract in Full Text. [source] Highly Selective Reaction of ,-Halo-,,,-unsaturated Esters with Ketones or Aldehydes Promoted by SmI2: An Efficient Alternative Access to Baylis,Hillman Adducts.CHEMINFORM, Issue 43 2005Jose M. Concellon Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Facile One-Pot Synthesis of ,-Iodo-,,,-unsaturated Esters.CHEMINFORM, Issue 39 2004Xingguo Zhang Abstract For Abstract see ChemInform Abstract in Full Text. [source] | ||||||||||||||||||||||