摘要
研究了醋酸铑[Rh2(OAc)4]、手性亚磺酰胺基脲和非手性磺酸共催化的α-重氮酯与酰胺化合物的不对称N—H插入反应.研究发现α-重氮酯在醋酸铑催化下形成金属卡宾,该金属卡宾与酰胺反应生成潜手性活泼叶立德中间体.在催化剂量的手性亚磺酰胺基脲和非手性磺酸存在下,潜手性叶立德中间体发生不对称质子化,合成了手性α-氨基酸衍生物.反应过程中,手性亚磺酰胺基脲和非手性磺酸作为"手性质子梭"催化不对称质子迁移从而实现了反应的对映选择性控制.该方法发展了非手性铑、手性亚磺酰胺基脲和非手性磺酸不对称共催化体系,为合成α-氨基酸衍生物提供了一种新途径,反应收率最高可达84%,对映选择性最高可达77%.
The enantioselective N—H insertion of α-diazoesters and carbamates provides a potentially attractive approach to α-amino acid derivatives. Herein, a novel cooperative catalytic system of achiral dirhodium(Ⅱ) acetates, chiral sulfonamide urea and achiral sulfonic acid was developed for asymmetric N—H insertion reactions. Prochiral ammonium ylide intermediates, generated in situ from α-diazoesters and carbamates initiated by dirhodium(Ⅱ) acetate, underwent asymmetric protonation with a considerable enantioselectivity in the presence of chiral sulfonamide urea and achiral sulfonic acid as co-catalysts. The co-catalysts of chiral sulfonamide urea and achiral sulfonic acid were considered as a chiral proton shuttle assisting the asymmetric proton transfer process to control the enantioselectivity. This methodology provides an efficient and mild approach to α-amino acid derivatives in high yields (up to 84% yield) with moderate enantioselectivity (up to 77% ee).
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2014年第1期107-111,共5页
Chinese Journal of Organic Chemistry
基金
国家杰出青年科学基金(No.21125209)
上海市科委重点基础研究基金(No.12JC1403800)
上海市闵行区高层次选拔人才计划资助项目~~