Catalytic Enantioselective Vinylogous Mannich Addition of Coumarins to Isatin Imines

• 作 者: Jing Wang Shuo Zhang Weizhong Ding Chenghan Wang Xiaoyu Wu
• 机 构: Center for Supramolecular Chemistry and Catalysis and Department of Chemistry,College of Sciences,Sh
• 出 处: 中国化学会第十六届全国有机合成化学学术研讨会
• 发表日期: 2019年3期
• 关键词: Asymmetric Vinylogous Mannich reaction Coumarin Oxindole

　　Coumarin is a privileged scaffold that frequently occurred in a large number of natural products,pharmaceuticals and agrochemicals.1 3-quaternary carbon oxindoles constitute the framework of a wide variety of natural products and biologically active compounds.2 Thus,the Mannich adducts generated from vinylogous addition of cyanocoumarins to isatin imines bearing two privileged pharmacores would be attractive compounds for biologically screening.Herein,we present our investigation of this Mannich reaction catalysed by as low as 0.1 mol%of chiral phosphonium salt catalyst,3 derived from amino alcohol with excellent yields and excellent enantioselectivities(Figure 1).The utility of this method was illustrated by an example of gram scale synthesis using as low as 0.1 mol%catalyst without a chromatography operation,and removal of the Boc protecting groups on the primary amine functionality in Mannich products.