聚合物支载的L-脯氨酸催化的直接不对称Aldol反应

Synthesis of Polymer-supported L-proline Catalyst and Study on Their Catalyzed Direct Asymmetric Aldol Reaction

制备了3种聚合物支载的L-脯氨酸催化剂6a^6c.以4-硝基苯甲醛、丙酮的Aldol反应为模型对它们的催化活性进行了筛选,6b为最佳催化剂,它催化的醛与丙酮的直接不对称Aldol反应(收率60%~68%,62%~82%ee)与L-脯氨酸催化的该反应(收率60%~68%,60%~85%ee)相当.6b可以通过结晶回收套用,反复使用5次催化效率不变.DMF,DMSO是最合适溶剂,催化剂用量以n(催化剂)∶n(醛)=1∶4最佳.

Three kinds of polymer-supported catalysts loaded L-proline 6a--6c were prepared and their catalytic activity were screened by the direct asymmetric aldol reaction of acetone and 4-nitrobenzaldehyde. The catalyst 6b was the best one among them. The yields and ee values （yield 60 %-68 %, 62 %--82 % ee） catalyzed by 6b were as well as that of L-proline （yield 60 % -68 % ,60 % -85 %ee）. 6b could be recoveried and reused by crystallization,and after reuse of the catalyst five times, there was no loss in activity. The DMSO and DMF was the suitable solvent and n （catalyst） ： n （aldehyde）=1：4 was best.