4,4′-DisubstitutedL-Prolines as Highly Enantioselective Catalysts for Direct Aldol Reactions
作者:Liuqun Gu、Menglong Yu、Xiaoyu Wu、Yazhu Zhang、Gang Zhao
DOI:10.1002/adsc.200606058
日期:2006.10
prolines (1a–h) has been developed and tested as organocatalysts in the direct catalytic asymmetric aldol reaction of several aliphatic ketones with aldehydes. Catalyst 1g affords the best enantioselectivities for this transformation. The reaction was carried out in DMF using a catalyst loading of 10 mol % at −10 °C to give the aldol products in up to 97 % ee for acetone. In the cases of cyclohexanone
已经开发了一系列新的4,4'-二取代脯氨酸(1a–h),并在几种脂肪族酮与醛的直接催化不对称醛醇缩合反应中作为有机催化剂进行了测试。1g催化剂为这种转化提供了最佳的对映选择性。该反应在-10°C下使用10 mol%的催化剂负载量在DMF中进行,得到的丙酮醛缩醛产品的产率最高为ee的97%。在环己酮和环戊酮的情况下,以94%ee获得了相应的抗产物。