N-(甘氨酸薄荷酯)-(+)-樟脑亚胺在烷基化反应中的双手性诱导效应

本文报道了从(+)-樟脑与(+)或(-)-甘氨酸薄荷醇酯所得的亚胺的烷基化反应, 烷基化产物经水解得到(R)-氨基酸。与N-(特丁氧羰基亚甲基)-(+)-樟脑亚胺相比,由于存在匹配的双手性诱导效应, 而使N-[甘氨酸-(+)-薄荷酯]-(+)-樟脑亚胺烷基化的立体选择性有明显的提高(43.8-98%),而不匹配的N-[甘氨酸-(-)-薄荷醇酯]-(+)-樟脑亚胺烷基化的立体选择性明显降低。它们的甲基化都给出(S)-丙氨酸, 且立体选择性不受薄荷酯的构型影响。

Double asymmetric induction in alkylation of the imines derived from(+)-camphor and (+)-or (-)-methyl glycinate

A double asym. induction effect has been observed in the alkylation of the imines derived from (+)-camphor and (+)- or (-)-menthyl glycinates. After hydrolysis of the alkylated intermediates, (R)-a-amino acids are obtained in 7.3-100% enantiomeric excess. Compared with the alkylation of the imine obtained from (+)-camphor of tert-Bu glycinate, the stereoselectivity of the alkylation of the (+)-menthyl imine is obviously enhanced. Using MeI as an alkylating reagent, (S)-alanine is obtained.