Highly enantioselective immobilized prolinamide-catalyzed aldol reactions in continuous-flow systems: effect of water on the catalyst lifetime and application in the synthesis of a chiral fenpentadiol analogue
作者:Caizhen Yue、Yasuhiro Yamashita、Shū Kobayashi
DOI:10.1039/d0gc04202a
日期:——
Catalytic enantioselectivealdolreactions of trifluoroacetophenones with ketones under continuous-flow conditions have been developed for the first time by using polystyrene-supported prolinamides. The robustness of the flow system was demonstrated by the continuous synthesis of a variety of trifluoromethyl carbinols in high yields with high enantioselectivities. The unusually long lifetimes (>195
Construction of Tertiary Alcohols Bearing Perfluoroalkyl Chains Catalyzed by Prolinamide-Thioureas
作者:Christoforos G. Kokotos
DOI:10.1021/jo2020104
日期:2012.1.20
A systematic study to evaluate the ability of various organocatalysts to catalyze the aldol reaction between acetone and 2,2,2-trifluoromethyl-l-phenylethanone was undertaken. Benchmark organocatalysts failed to catalyze this reaction. However, a prolinamide-thiourea consisting of (S)-prolinamide, (1S,2S)-diphenylethylenediamine, and (S)-ditert butyl aspartate proved to be an efficient catalyst, providing tertiary alcohols as the products of the reaction between ketones and perfluoroalkyl ketones in high to quantitative yields and high enantioselectivities (up 81% ee) at a catalyst loading of 2 mol %.