Thiourea-Catalyzed Highly Enantio- and Diastereoselective Additions of Oxindoles to Nitroolefins: Application to the Formal Synthesis of (+)-Physostigmine
作者:Tommy Bui、Salahuddin Syed、Carlos F. Barbas
DOI:10.1021/ja903520c
日期:2009.7.1
molecules. Most catalytic methods for the asymmetric syntheses of these compounds rely heavily on the use of transition-metal catalysts. In contrast, alternative catalytic procedures involving organocatalysis are scarce. Herein we disclose a conceptually novel organocatalytic approach to the syntheses of these materials using thiourea-catalyzed asymmetric 1,4-additions of oxindole derivatives to nitroolefins
Expanding the Scope of Cinchona Alkaloid-Catalyzed Enantioselective α-Aminations of Oxindoles: A Versatile Approach to Optically Active 3-Amino-2-oxindole Derivatives
作者:Tommy Bui、Mar Borregan、Carlos F. Barbas
DOI:10.1021/jo902039a
日期:2009.12.4
A cinchona alkaloid-catalyzed, highly enantioselective, α-amination of oxindoles has been developed. The reaction is general, operationally simple, and affords the desired products in high yields with good to excellent enantioselectivity. Significantly, this study provides a general catalytic method for the construction of a C−N bond at the C3 position of oxindoles as well as for the creation of a
An enantioselective direct α-alkylation of 2-oxindoles with Michler's hydrol via an SN1-type pathway in the non-covalent activation mode using the bis-cinchona alkaloid and Brønsted acid as a co-catalyst was developed and good to high yields and enantioselectivities were obtained.
Organocatalytic Asymmetric Conjugate Addition of 3-Alkyl-Substituted Oxindoles to Vinyl Ketones
作者:Hyun-Joo Lee、Dae-Young Kim
DOI:10.5012/bkcs.2012.33.10.3171
日期:2012.10.20
enantioselective conjugate addition reaction of 3-aryl-substituted oxindoles to vinyl ketones, 5 a few examples for the catalytic enantioselective conjugate addition reaction of 3alkyl-substituted oxindoles to cyclic enones were reported using chiral primary or secondaryamine catalysts. 6 Therefore, the development of alternative catalysts for the catalytic enantioselective conjugate addition reaction of 3-alkyl-substituted
Organocatalytic asymmetric Michael addition of 3-substituted oxindoles to α,β-unsaturated acyl phosphonates for the synthesis of 3,3′-disubstituted oxindoles with chiral squaramides
The first Michael addition of 3-monosubstituted oxindoles to α,β-unsaturated acyl phosphonates is investigated to give 3,3′-disubstituted oxindoles with excellent results.