Highly Enantioselective Organocatalyzed Construction of Quaternary Carbon Centers via Cross-Aldol Reaction of Ketones in Water
作者:Changwu Zheng、Yongyong Wu、Xiaosheng Wang、Gang Zhao
DOI:10.1002/adsc.200800248
日期:——
The asymmetric construction of quaternary carbon centers via cross-aldol reactions of ketones with β,γ-unsaturated keto esters catalyzed by 4-(tert-butyldiphenylsilyloxy)-pyrrolidine-2-carboxylic acid in water is described. The adducts bearing two adjacent chiral centers were obtained in high yields, mostly up to 99% ee, and with high diastereoselectivities. The corresponding polyfunctional products
季碳中心的非对称结构通过与β酮的交叉醛醇缩合反应,γ不饱和酮酯由4-(催化叔-butyldiphenylsilyloxy) -吡咯烷-2-羧酸在水中的酸进行说明。带有两个相邻手性中心的加合物以高收率获得,大多数是高达99%ee,并且具有非对映选择性。相应的多官能产物也可以容易地转化为具有三个手性中心的有用的内酯。