Enantiopure azetidine-2-carboxamides as organocatalysts for direct asymmetric aldol reactions in aqueous and organic media
作者:Xixi Song、Ai-Xiang Liu、Shan-Shan Liu、Wen-Chao Gao、Min-Can Wang、Junbiao Chang
DOI:10.1016/j.tet.2013.12.081
日期:2014.2
A family of enantiopure azetidine-2-caboxamides was asymmetrically synthesized, and was examined as organocatalyst in direct aldol reactions. A well chosen chiral azetidine-2-caboxamide was found to smoothly catalyze the direct aldol reaction of various benzaldehydes with acetone in brine, and beta-hydroxy ketones were produced with enantiomeric excess up to 96%. The reaction of benzaldehydes with cyclic ketones also led to the formation of anti-products in diastereomeric ratio up to 99:1 and enantiomeric excess up to 99%. (c) 2014 Elsevier Ltd. All rights reserved.