Key Laboratory of Small Functional Organic Molecule, Ministry of Education and Jiangxi Key Laboratory of Green Chemistry, Jiangxi Normal University, Nanchang, Jiangxi 330022, China.
Jiangxi Provincial Research of Targeting Pharmaceutical Engineering Technology, Shangrao Normal University, Shangrao, Jiangxi 334001, China.
J Org Chem. 2020 Dec 4;85(23):14963-14970. doi: 10.1021/acs.joc.0c01782. Epub 2020 Nov 2.
The first highly enantioselective construction of chiral cyclopropa[]coumarins was described. Using commercially available (bis)cinchona alkaloid (DHQ)PYR as the chiral Lewis base catalyst, together with CsCO as the achiral base, the reaction of a series of coumarin-3-carboxylate and 3-benzoyl coumarins with -butyl 2-bromoacetate could give rise to the corresponding cyclopropa[]coumarins bearing three continuous chiral stereocenters in 83-93% ee and 90-97% ee, respectively. The reaction is proposed to proceed via an generated ammonium ylide intermediate.
首次实现了手性环丙[]香豆素的高对映选择性构建。使用商业可得的（双）金鸡纳碱（DHQ）PYR 作为手性路易斯碱催化剂，与 CsCO3 作为非手性碱一起，一系列香豆素-3-羧酸酯和 3-苯甲酰基香豆素与 -丁基 2-溴代乙酸酯的反应可以得到相应的环丙[]香豆素，对映选择性分别为 83-93%ee 和 90-97%ee，产物中含有三个连续的手性中心。该反应被认为是通过生成的铵叶立德中间体进行的。
