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Highly Enantioselective (highly + enantioselective)
Terms modified by Highly Enantioselective Selected AbstractsA Highly Enantioselective and Catalytic Aryl Transfer Reaction Using Mixed Triarylbismuthane and Dialkylzinc ReagentsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2007Itaru Sato Abstract Highly enantioselective and catalytic aryl transfer reactions to aromatic aldehydes by using mixed triarylbismuthane and dimethylzinc reagents were studied. In the presence of a chiral ,-amino alcohol catalyst, chiral diarylmethanols with up to 97,% ee were obtained. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Organocatalyzed Highly Enantioselective and anti -Selective Construction of ,-Butenolides through Vinylogous Mukaiyama Aldol ReactionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 8 2010Ning Zhu Abstract The formation of chiral ,-butenolides has been achieved with good yields (up to 90%), high enantioselectivity (up to 91%) and diastereoselectivity (up to 9/1, anti -selective) through an organocatalyzed vinylogous Mukaiyama aldol reaction of 2-(trimethylsilyloxy)furan and aldehydes. A wide range of chiral ,-butenolides was obtained under mild conditions by this methodology. [source] Tuning Electronic and Steric Effects: Highly Enantioselective [4+1] Pyrroline Annulation of Sulfur Ylides with ,,,-Unsaturated Imines,ANGEWANDTE CHEMIE, Issue 26 2010Liang-Qiu Lu Sterische und elektronische Effekte: Mithilfe einer neuartigen [4+1]-Cycloaddition von atropisomeren Schwefel-Yliden 1 und ungesättigten Iminen 2 gelingt die Synthese enantiomerenangereicherter Pyrroline 3 in hohen Ausbeuten. Die beobachteten hohen Stereoselektivitäten wurden anhand einer Konformationsanalyse der Ylide erklärt. [source] ChemInform Abstract: Chiral Spiroaminoborate Ester as a Highly Enantioselective and Efficient Catalyst for the Borane Reduction of Furyl, Thiophene, Chroman, and Thiochroman-Containing Ketones.CHEMINFORM, Issue 23 2010Viatcheslav Stepanenko 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: Titanium Binolate Catalyzed Aminolysis of meso Aziridines: A Highly Enantioselective and Direct Access to 1,2-Diamines.CHEMINFORM, Issue 42 2009Saravanan Peruncheralathan 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 Enantioselective 1,3-Dipolar Cycloaddition of Azomethine Ylides Catalyzed by AgOAc/TF-BiphamPhos.CHEMINFORM, Issue 41 2009Chun-Jiang 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 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 Enantioselective 1,4-Addition of Diethyl Phosphite to Enones Using a Dinuclear Zn Catalyst.CHEMINFORM, Issue 28 2009Depeng Zhao 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: Cationic Palladium(II)-Catalyzed Highly Enantioselective [3 + 2] Annulation of 2-Acylarylboronic Acids with Substituted Alkynes.CHEMINFORM, Issue 17 2008Miao Yang 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] Organocatalytic Highly Enantioselective ,-Arylation of ,-Ketoesters.CHEMINFORM, Issue 47 2007Jose Aleman 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] Lyophilization of Lipase Together with Ionic Compounds Generates Highly Enantioselective and Solvent-Sensitive Lipase in Organic Solvents.CHEMINFORM, Issue 24 2005Shin-ichi Ueji Abstract For Abstract see ChemInform Abstract in Full Text. [source] An Amine Sulfonamide Organocatalyst for Promoting Direct, Highly Enantioselective ,-Aminoxylation Reactions of Aldehydes and Ketones.CHEMINFORM, Issue 3 2005Wei Wang Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: A Highly Enantioselective and General Conjugate Addition of Thiols to Cyclic Enones with an Organic Catalyst.CHEMINFORM, Issue 29 2002Paul McDaid 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] A Highly Enantioselective and Catalytic Aryl Transfer Reaction Using Mixed Triarylbismuthane and Dialkylzinc ReagentsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2007Itaru Sato Abstract Highly enantioselective and catalytic aryl transfer reactions to aromatic aldehydes by using mixed triarylbismuthane and dimethylzinc reagents were studied. In the presence of a chiral ,-amino alcohol catalyst, chiral diarylmethanols with up to 97,% ee were obtained. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Rhodium-Catalyzed Asymmetric Nitroallylation of Arylmetallics with Cyclic Nitroallyl Acetates and Applications in Organic SynthesisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2006Lin Dong Abstract Highly enantioselective rhodium-catalyzed nitroallylations of arylboronic acids and arylzinc chlorides with cyclic nitroallyl acetates are described. Catalyst screening indicated that the rhodium complex of [Rh(OH)(COD)]2 and optically pure binap is the optimal catalyst for the nitroallylation of arylboronic acids with 2-nitrocyclohex-2-enyl esters, providing good yields and high enantioselectivities of up to 99,% ee. The rhodium complex prepared from Rh(acac)(C2H4)2 and (R)-binap efficiently catalyzed the nitroallylation of arylzinc chlorides with 2-nitrocyclohex-2-enyl acetate at 0 °C in high yields of up to 93,% and with high enantioselectivities of up to 96,% ee. A number of synthetically useful intermediates with high optical purity were prepared with this reaction as starting point: concise total syntheses of optically pure (+)-,-lycorane in 53,% overall yield and of (+)-,-lycorane in 52,% overall yield were achieved by commencing with the asymmetric nitroallylation of 3,4-methylenedioxyphenylzinc chloride with 2-nitrocyclohex-2-enyl acetate. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] A Novel Cost-Effective Thiourea Bifunctional Organocatalyst for Highly Enantioselective Alcoholysis of meso -Cyclic Anhydrides: Enhanced Enantioselectivity by Configuration InversionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009Su-Xi Wang Abstract A novel inexpensive thiourea bifunctional organocatalyst which can promote the highly enantioselective (up to 95% ee) alcoholysis of meso -cyclic anhydrides has been developed. Computational studies on the catalytic process as well as a synthetic application of this new catalyst are also presented. [source] Chiral Phosphoric Acid-Catalyzed Enantioselective Aza-Friedel,Crafts Reaction of IndolesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2007Masahiro Terada Abstract A highly enantioselective 1,2-aza-Friedel,Crafts reaction of N - tert -butyldimethylsilylindole with N - tert -butoxycarbonyl aromatic imines is demonstrated using a BINOL-derived monophosphoric acid catalyst. The present approach provides efficient access to 3-indolylmethaneamines with aryl substituents in excellent enantioselectivities (up to 98,% ee). An inversion in the sense of enantioselection was found between monophosphoric acid catalysts bearing different substituents introduced at the 3,3,-position of binaphthyl backbone. We also calculated the three-dimensional structure of the monophosphoric acid catalysts to speculate on the inversion of the stereochemical outcome. [source] Kinetic Resolution of 1-Biaryl- and 1-(Pyridylphenyl)alkan-1-ols Catalysed by the Lipase B from Candida antarcticaADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2005Robert Kourist Abstract Lipase B from Candida antarctica (CAL-B) catalyses the highly enantioselective (E>200) transesterification of some 1-biaryl-2-yl-, -3-yl-, and -4-ylethanols and -propan-1-ols, as well as 1-(o -, m -, and p -pyridylphenyl)ethanols, 6, with vinyl acetate, Kazlauskas' rule being obeyed in all cases. meta and para -Substituted substrates were transformed within several hours (conversion degree ranging from 23,50%), reaction rates for propan-1-ol derivatives being slower than those for ethanol derivatives. Transesterifications of ortho -substituted alcohols took several days and were accompanied by a chemoenzymatic side reaction: the formation of another acetate derived from the hemiacetal between 6 and acetaldehyde coming from vinyl acetate. This side reaction was suppressed in the presence of isopropenyl acetate as acyl donor, conversion degrees for transesterification ranging from 20,40% after ten days (E>200). The usefulness of (R)- 6p as ligand in the asymmetric addition of diethylzinc to benzaldehyde was also demonstrated. [source] 1H and 13C NMR assignments of all three isomeric o -fluoronaphthaldehydes and three o -fluorophenanthrene aldehydesMAGNETIC RESONANCE IN CHEMISTRY, Issue 1 2010Carl A. Busacca Abstract Three isomeric o -fluoronaphthaldehydes, 9-fluorophenanthrene, and three previously unreported o -fluorophenanthrene aldehydes were analyzed in detail by multiple NMR techniques to provide unambiguous assignment of structures and resonances. The six aldehydes serve as the key starting materials for novel chiral ligands used in highly enantioselective rhodium-catalyzed asymmetric hydrogenation reactions. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||