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Enantioselective Michael Addition (enantioselective + michael_addition)
Kinds of Enantioselective Michael Addition Selected AbstractsSynthesis of Binaphthyl Sulfonimides and Their Application in the Enantioselective Michael Addition of Ketones to NitroalkenesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 27 2010Shurong Ban Abstract Novel types of L -proline-based binaphthyl sulfonimides and sulfonamides were found to be efficient organocatalysts for the asymmetric Michael addition of ketones to nitroalkenes to provide optically active ,-nitroketone derivatives of synthetic and biological importance. After the fine optimization of solvents, temperature, and additive, good to excellent enantioselectivities and diastereoselectivities (71,96,%,ee, up to >99:1,dr) can be achieved. [source] Enantioselective Michael Addition of Aromatic Ketones to Nitroolefins Catalyzed by Bifunctional Thioureas and Mechanistic InsightEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2010Bai-Lin Li Abstract A highly enantioselective Michael reaction of aromatic ketones with nitroolefins was accomplished in the presence of a chiral bifunctional primary amine,thiourea catalyst and 4-nitrobenzoic acid as the co-catalyst; the corresponding adducts were obtained in excellent enantioselectivities (up to 99,%,ee) and yields (up to 98,%). The catalytic mechanism of the Michael reaction was confirmed through the ESI-MS detection of proposed reaction intermediates and the 1H NMR detection of hydrogen bonding between thiourea and the nitroolefins. DFT calculations showed that chiral moieties of the thiourea impacted the yields and enantioselectivities of the adducts remarkably, which corresponds to the observed experimental results. [source] Organocatalytic Enantioselective Michael Addition of 4-Hydroxycoumarin to ,,,-Unsaturated Ketones: A Simple Synthesis of WarfarinEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 30 2009Zhenhua Dong Abstract A type of C2 -symmetric secondary amine amide catalysts were developed for the asymmetric Michael addition of 4-hydroxycoumarin to ,,,-unsaturated ketones. A series of important biologically and pharmaceutically active compounds were obtained in excellent yields (up to 99,%) with high enantioselectivities (up to 89,%,ee) under mild conditions. In addition, enantiopure product could be obtained by a single recrystallization. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Highly Enantioselective Michael Addition of Cyclic 1,3-Dicarbonyl Compounds to ,,,-Unsaturated ,-Keto EstersADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Xing-Kuan Chen Abstract A highly enantioselective Michael addition of cyclic 1,3-dicarbonyl compounds to ,,,-unsaturated ,-keto esters catalyzed by amino acid-derived thiourea-tertiary-amine catalysts is presented. Using 5,mol% of a novel tyrosine-derived thiourea catalyst, a series of chiral coumarin derivatives were obtained in excellent yields (up to 99%) and with up to 96% ee under very mild conditions within a short reaction time. [source] Back to Natural Cinchona Alkaloids: Highly Enantioselective Michael Addition of Malononitrile to EnonesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Alessio Russo Abstract An efficient and convenient highly enantioselective Michael addition of malononitrile to enones has been developed by using quinine as the organocatalyst. The adducts were isolated in excellent yield and high asymmetric induction (up to 95% ee). An easy route to difficultly accessible ester derivatives has been also disclosed. [source] Highly Efficient Ion-Tagged Catalyst for the Enantioselective Michael Addition of Aldehydes to NitroalkenesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Marco Lombardo Abstract The ion-tagged diphenylprolinol silyl ether 6 very efficiently catalyzes the asymmetric Michael addition of aliphatic aldehydes to nitroalkenes with ee of up to>99.5% at low catalyst loadings (0.25,5,mol%) and using only a slight excess of aldehydes (1.2,2,equiv.). This new organocatalyst can be used with the same outstanding efficiency in a wide variety of solvents and reaction conditions. [source] Highly Enantioselective Michael Addition of ,-Substituted Cyano Ketones to ,,,-Unsaturated ,-Keto Esters using Bifunctional Thiourea-Tertiary Amine Catalysts: An Easy Access to Chiral DihydropyransADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Sheng-Li Zhao Abstract An asymmetric Michael addition of ,-substituted cyano ketones to ,,,-unsaturated ,-keto esters to form chiral dihydropyrans catalyzed by a series of ,-amino acid-derived thiourea-tertiary amines is presented. A novel tyrosine-derived thiourea catalyst was identified as the optimal catalyst providing the desired product in 91,95% yields and with 90,96% ee at a low catalyst loading of 2.0,mol%. The utility of the reaction was exemplified by facile conversion of the dihydropyran product into pharmaceutically useful dihydropyridine. [source] Enantioselective Michael Addition of Dicyanoolefins to ,,,-Unsaturated Aldehydes in Aqueous MediumADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2008Jun Lu Abstract A pool of water-compatible catalysts, namely dialkyl-(S)-prolinols, has been developed for the enantioselective direct vinylogous Michael addition reaction of vinylmalononitriles to ,,,-unsaturated aldehydes in aqueous medium. In many cases, the products can be obtained in almost optically pure form (>96% ee) after a single recrystallization. [source] Squaramide-Catalyzed Enantioselective Michael Addition of Diphenyl Phosphite to Nitroalkenes,ANGEWANDTE CHEMIE, Issue 1 2010Ye Zhu Einfach zugänglich ist der im Schema gezeigte Squaramidkatalysator, der die hoch enantioselektive Michael-Addition von Diphenylphosphit an Nitroalkene vermittelt. Dieser Ansatz führt zu chiralen ,-Nitrophosphonaten, die Vorstufen für biologisch aktive ,-Aminophosphonsäuren sind. [source] ChemInform Abstract: Noyori,s Ts-DPEN Ligand: Simple Yet Effective Catalyst for the Highly Enantioselective Michael Addition of Acetone to Nitroalkenes.CHEMINFORM, Issue 35 2010Lin Peng No abstract is available for this article. [source] ChemInform Abstract: Chiral Bifunctional Thiourea-Catalyzed Enantioselective Michael Addition of Ketones to Nitrodienes.CHEMINFORM, Issue 25 2010Hai Ma 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: Enantioselective Michael Addition to ,,,-Unsaturated Aldehydes: Combinatorial Catalyst Preparation and Screening, Reaction Optimization, and Mechanistic Studies.CHEMINFORM, Issue 19 2010Ivana Fleischer 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: Enantioselective Michael Addition of Malononitrile to Chalcones Catalyzed by a Simple Quinine,Al(OiPr)3 Complex: A Simple Method for the Synthesis of a Chiral 4H-Pyran Derivative.CHEMINFORM, Issue 51 2009Jian Shi 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: Ionic Liquid Supported (ILS) (S)-Pyrrolidine Sulfonamide, a Recyclable Organocatalyst for the Highly Enantioselective Michael Addition to Nitroolefins.CHEMINFORM, Issue 27 2009Bukuo Ni 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: Enantioselective Michael Addition of Nitroolefins and Cyclohexanones Catalyzed by Novel Pyrrolidine-thiourea Bifunctional Catalysts with Two Chiral Centers.CHEMINFORM, Issue 44 2008Dongping Cheng 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: Organocatalytic Highly Enantioselective Michael Addition of 2-Hydroxy-1,4-naphthoquinones to Nitroalkenes.CHEMINFORM, Issue 44 2008Wen-Ming Zhou 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 Michael Addition of Malononitrile to ,,,-Unsaturated Ketones.CHEMINFORM, Issue 21 2008Xuefeng Li 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: An Enantioselective Michael Addition of Malonate to Nitroalkenes Catalyzed by Low Loading Demethylquinine Salts in Water.CHEMINFORM, Issue 11 2008Fu-Xin Chen 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: Pyrrolidine,Pyridinium Based Organocatalysts for Highly Enantioselective Michael Addition of Cyclohexanone to Nitroalkenes.CHEMINFORM, Issue 3 2008Dan-Qian Xu 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] Enantioselective Michael Addition to ,,,-Unsaturated Imides Catalyzed by a Bifunctional Organocatalyst.CHEMINFORM, Issue 44 2005Yasutaka Hoashi Abstract For Abstract see ChemInform Abstract in Full Text. [source] Direct Enantioselective Michael Addition of Aldehydes to Vinyl Ketones Catalyzed by Chiral Amines.CHEMINFORM, Issue 39 2003Paolo Melchiorre Abstract For Abstract see ChemInform Abstract in Full Text. [source] Highly Enantioselective Michael Addition of Malononitrile to Vinylogous Imine Intermediates Generated in situ from Arylsulfonyl IndolesCHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2010Linhai Jing Malononitrile on rare form: Highly enantioselective Michael addition of malononitrile to vinylogous imine intermediates 2, generated in situ from arylsulfonyl indoles 1, is described (see scheme). This protocol provides easy and convenient access to valuable 3-indolyl derivatives 3 in high yields and enantioselectivities. A possible catalytic mechanism is proposed. [source] Enantioselective Michael Additions of ,-Keto Esters to ,,,-Unsaturated Carbonyl Compounds Catalyzed by a Chiral Biquinoline N,N,-Dioxide-Scandium Trifluoromethanesulfonate Complex.CHEMINFORM, Issue 52 2003Makoto Nakajima Abstract For Abstract see ChemInform Abstract in Full Text. [source] Highly Enantioselective Michael Addition of Cyclic 1,3-Dicarbonyl Compounds to ,,,-Unsaturated ,-Keto EstersADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Xing-Kuan Chen Abstract A highly enantioselective Michael addition of cyclic 1,3-dicarbonyl compounds to ,,,-unsaturated ,-keto esters catalyzed by amino acid-derived thiourea-tertiary-amine catalysts is presented. Using 5,mol% of a novel tyrosine-derived thiourea catalyst, a series of chiral coumarin derivatives were obtained in excellent yields (up to 99%) and with up to 96% ee under very mild conditions within a short reaction time. [source] Highly Enantioselective Michael Addition Reactions of 3-Substituted Benzofuran-2(3H)-ones to Chalcones Catalyzed by a Chiral Alkyl-Substituted ThioureaADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010Xin Li Abstract A highly enantioselective Michael addition of 3-substituted benzofuran-2(3H)-ones to chalcones catalyzed by a chiral bifunctional thiourea was developed. Several chiral 3,3,-substituted benzofuran-2(3H)-ones derivatives, bearing adjacent quaternary-tertiary stereocenters, were efficiently synthesized with excellent enantioselectivities. [source] Back to Natural Cinchona Alkaloids: Highly Enantioselective Michael Addition of Malononitrile to EnonesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Alessio Russo Abstract An efficient and convenient highly enantioselective Michael addition of malononitrile to enones has been developed by using quinine as the organocatalyst. The adducts were isolated in excellent yield and high asymmetric induction (up to 95% ee). An easy route to difficultly accessible ester derivatives has been also disclosed. [source] Highly Enantioselective Michael Addition of Malononitrile to Vinylogous Imine Intermediates Generated in situ from Arylsulfonyl IndolesCHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2010Linhai Jing Malononitrile on rare form: Highly enantioselective Michael addition of malononitrile to vinylogous imine intermediates 2, generated in situ from arylsulfonyl indoles 1, is described (see scheme). This protocol provides easy and convenient access to valuable 3-indolyl derivatives 3 in high yields and enantioselectivities. A possible catalytic mechanism is proposed. [source] Catalytic activation through metal enolization of nucleophile precursors and synthetic applications to enantioselective Michael additionsTHE CHEMICAL RECORD, Issue 3 2007Shuji Kanemasa Abstract Catalytic activation methods of nucleophile precursors recently developed in our research group were reviewed in this paper. These include (i) the catalytic double activation method of nucleophile precursors through enol formation and of electrophiles through coordination in alcohols; (ii) the double catalytic activation method by use of both catalytic amounts of chiral Lewis acid and external achiral amine; (iii) the catalytic activation method of nucleophile precursors with a chiral cationic Lewis acid in the presence of molecular sieves; and (iv) the single catalytic activation of nucleophile precursors through metal enolization in alcohol media. © 2007 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 7: 137,149; 2007: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20105 [source] | ||||||||||||||||||||||