标题：A Highly Efficient Organocatalyst for Direct Aldol Reactions of Ketones with Aldedydes
来源：《美国化学会志》2005年127卷25期9285-9289页
作者：中科院成都有机化学研究所 Zhuo Tang（唐卓）, Zhi-Hua Yang, Xiao-Hua Chen, Lin-Feng Cun（寸琳峰）, Ai-Qiao Mi（宓爱巧）, Yao-Zhong Jiang（蒋耀忠）, Liu-Zhu Gong（龚流柱）
Research Fronts:DIRECT ENANTIOSELECTIVE ALDOL REACTIONS; DIRECT ASYMMETRIC ALDOL REACTION; DIRECT ALDOL REACTIONS; DIRECT ALDOL CONDENSATION; HIGHLY EFFICIENT ORGANOCATALYST
领域：化学
L-Proline amides derived from various chiral -amino alcohols that bear substituents with various electron natures at their stereogenic centers are prepared and evaluated for catalyzing the direct Aldol reaction of 4-nitrobenzaldehyde with acetone. Catalysts with strong electron-withdrawing groups are found to exhibit higher catalytic activity and enantioselectivity than their analogues with electron-donating groups. The presence of 2 mol % catalyst 4g significantly catalyzes the direct Aldol reactions of a wide range of aldehydes with acetone and butanone, to give the -hydroxy ketones with very high enantioselectivities ranging from 96% to >99% ee. High diastereoselectivity of 95/5 was observed for the anti Aldol product from the reaction of cyclohexanone, and excellent enantioselectivity of 93% ee was provided for anti Aldol product from the reaction of cyclopentanone.
