New chiral N-heterocyclic olefin bifunctional organocatalysis inα-functionalization ofβ-ketoesters  

作　　者：Sijing Wang Cefei Zhang Da Li Yuqiao Zhou Zhishan Su Xiaoming Feng Shunxi Dong 

机构地区：[1]Key Laboratory of Green Chemistry&Technology,Ministry of Education,College of Chemistry,Sichuan University,Chengdu 610064,China

出　　处：《Science China Chemistry》2023年第1期147-154,共8页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(92056107,22271199,21801175);the Sichuan University(2020SCUNL204)。

摘　　要：N-heterocyclic olefins(NHOs)possess an electron-rich and highly polarized C=C double bond due to the donating property of nitrogen atoms.This feature imparts exocyclic carbon atom of NHOs with strong basicity and high nucleophilicity.Although NHOs have been emerging as a new type of organocatalyst and ligand for metal complexes in organic synthesis,chiral NHOmediated highly enantioselective organic transformations were still elusive.Herein,we developed a new type of chiral aminederived C_(2)-symmetric NHOs and employed them as efficient chiral bifunctional organocatalysts for asymmetricα-functionalization ofβ-ketoesters.With as low as 0.1 mol%catalyst loading,the desired amination and trifluoromethylthiolation products were afforded in good yields with high enantioselectivities(up to 99%yield and 99%ee).Experimental studies and theoretical calculation disclosed that hydrogen-bonding interaction upon protonation and other weak interaction between substrate and catalyst were crucial for the enantiocontrol.

关 键 词：ORGANOCATALYST N-heterocyclic olefin asymmetric synthesis amination trifluoromethylthiolation 

分 类 号：O621.251[理学—有机化学]