L-脯氨酰-L-苯丙氨酸催化的直接不对称Mannich反应研究

报道了L-脯氨酰-L-苯丙氨酸和L-脯氨酰-L-苯丙氨酸/对甲苯磺酸在DMSO中0℃催化硝基苯甲醛、丙酮与4-甲氧基苯胺一锅三组分的不对称Mannich反应。以L-脯氨酰-L-苯丙氨酸和L-脯氨酰-L-苯丙氨酸/对甲苯磺酸为催化剂,产物收率分别为56%和61%,ee值分别为98%和99%。实验得出低温有利于提高反应的对映选择性,4-甲氧基苯胺是最好的胺组分,催化剂对醛的结构要求苛刻。

Study on L-pro-L-phe catalyzed direct asymmetric Mannich-type reactions

The new three component one-pot direct asymmetric Mannich type reaction catalyzed by L-pro-L-phe and L-pro-L- phe/p-TsOH were investigated. Acetone, nitrobenzaldehyde and p-anisidine were used as substrates, and the results demonstrated that the L-pro-L-phe and L-pro-L-phe/p-TsOH could smoothly catalyze the direct asymmetric Mannich-type reaction in DMSO at 0℃ with up to 98%ee, 99% ee and 56%, 61% yields respectively. The lower temperature leads to a higher enantioselectivity and the p-anisidine produces the best results. There existed the crucial structure matching between catalysts and aldehydes under these reaction conditions.