Michael addition reaction of iminoglycinate 7 to ethyl γ-silyloxycrotonate with >98:<2 diastereoselectivity followed by hydrolysis and lactamization. Formal syntheses of (-)-isoretronecanol and (+)-laburnine as well as a concise enantioselective synthesis of (+)-turneforcidine could be achieved from functionalized pyroglutamates 15 or 16.
官能化的焦谷
氨酸盐15和16的合成可通过应用最近开发的
亚氨基甘氨酸盐7与非对映异构体的非对映迈克尔不对称迈克尔加成反应与非对映异构体> 98:<2的γ-甲硅烷基巴豆酸乙酯进行水解和内酰胺化来实现。从功能化的焦谷氨酸酯15或16可以实现(-)-
异戊烯醇和(+)-玫瑰花碱的形式合成以及(+)-turneforcidine的简明对映选择性合成。