Biomimetic asymmetric aldol reactions catalyzed by proline derivatives attached to β-cyclodextrin in water
作者:Hai-Min Shen、Hong-Bing Ji
DOI:10.1016/j.tetlet.2012.04.140
日期:2012.7
Two proline derivatives, (S)-2-aminomethylpyrrolidine and (R)-2-aminomethylpyrrolidine modified beta-CD (CD-1, CD-2) were synthesized in the yields of 31% and 14%. Their self-inclusion conformations were characterized by H-1 ROESY NMR studies and quantum calculation. When CD-1 was applied to asymmetric aldol reactions, up to 94% ee was obtained. Substrate selectivity was also observed in these asymmetric aldol reactions. (C) 2012 Elsevier Ltd. All rights reserved.
A Highly Efficient Organocatalyst for Direct Aldol Reactions of Ketones with Aldedydes
作者:Zhuo Tang、Zhi-Hua Yang、Xiao-Hua Chen、Lin-Feng Cun、Ai-Qiao Mi、Yao-Zhong Jiang、Liu-Zhu Gong
DOI:10.1021/ja0510156
日期:2005.6.1
prepared and evaluated for catalyzing the directAldolreaction 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 directAldolreactions of a wide range of aldehydes with acetone