Highly Enantioselective Cascade Reaction Catalyzed by Squaramides: the Synthesis of CF3-Containing Chromanes
摘要:
A catalytic asymmetric method for the synthesis of 2-CF3 chromanes has been described. Generally, the squaramide-catalyzed cascade reaction of 2-hydroxychalcones with beta-CF3-nitroalkenes gave the CF3-containing heterocyclic compounds bearing three contiguous stereogenic centers in excellent yields, diastereoselectivities, and enantioselectivities.
Highly Enantioselective Organocatalyzed Vinylogous Michael-Type Reaction for the Construction of Trifluoromethylated All-Carbon Quaternary Stereocenters
作者:Qiao Chen、Guoqiang Wang、Xianxing Jiang、Zhaoqing Xu、Li Lin、Rui Wang
DOI:10.1021/ol500157b
日期:2014.3.7
The first example of a highlyenantioselectivevinylogous Michael-type reaction of β,β-disubstituted nitroalkenes is disclosed. A series of biologically important chiral oxindoles, featuring a trifluoromethylated all-carbon quaternary chiral center, were obtained in good yields with excellent enantioselectivities (up to >99% ee).