Highly enantio- and diastereoselective Michael addition of cyclohexanone to nitroolefins catalyzed by a chiral glucose-based bifunctional secondary amine-thiourea catalyst
A novel bifunctional thiourea bearing a saccharide-scaffold and a secondary amino group was synthesized, and was proven to be an effective organocatalyst for the asymmetric Michael reaction of cyclohexanone to both aryl and alkyl nitroolefins. The corresponding adducts were obtained with excellent diastereo- (up to >99/1 dr) and enantioselectivities (up to 97% ee).
C3-Symmetric Proline-Functionalized Organocatalysts: Enantioselective Michael Addition Reactions
作者:Jarugu Narasimha Moorthy、Satyajit Saha
DOI:10.1002/ejoc.201000569
日期:2010.11
C 3 -Symmetric, tripodal catalyst 4 based on 1,3,5-triethylbenzene, which incorporates the features of a molecular receptor, is shown to catalyze Michaeladditionreactions of carbonyl compounds to β-nitrostyrenes in a high stereoselectivity (up to 99:1 dr and up to 98 % ee).
基于 1,3,5-三乙苯的 C 3 -对称三足催化剂 4 结合了分子受体的特征,显示出以高立体选择性(高达 99: 1 dr 和高达 98 % ee)。
Novel bifunctional chiral squaramide-amine catalysts for highly enantioselective addition of mono and diketones to nitroalkenes
Novelbifunctionalchiralsquaramide–amine organocatalysts have been developed by rational combination of pyrrolidine and a cinchona alkaloid. The catalysts promoted the enantioselective Michael addition of both mono- and diketones to a broad range of nitroalkenes providing the corresponding products in moderate to high yields with excellent enantioselectivities and diastereoselectivities (up to 96%
Ion-Supported Chiral Pyrrolidines as Enantioselective Catalysts for Direct Michael Addition of Nitroalkenes in [BMIm]PF<sub>6</sub>
作者:Zhenyuan Xu、Danqian Xu、Shuping Luo、Huadong Yue、Liping Wang、Yunkui Liu
DOI:10.1055/s-2006-950443
日期:2006.9
Imidazolium-supported-pyrrolidine-catalyzed asymmetric Michaeladdition reactions of unmodified ketones and aldehydes to nitroalkenes were performed in [BMIm]PF 6 to give products in up to 98% yield and 99% enantioselectivity. The catalytic system presented a synergistic effect in the improvement of reaction performance and could be recycled.
A novel and effective organocatalytic system consisting of pyrrolidinyl-thioimidazole and a chiral thioureido acid efficiently catalyzed the asymmetric Michaeladdition reactions of ketones to nitroolefins to afford the adducts with high diastereoselectivities (up to 99 : 1) and excellent enantioselectivities (up to 99% ee).