Enantioselective Trifluoromethylalkynylation of Alkenes via Copper-Catalyzed Radical Relay.

A novel enantioselective copper-catalyzed trifluoromethylalkynylation of styrenes, proceeding through a radical relay process, is described herein, which affords structurally diverse CF3-containing propargylic compounds in good yield with excellent enantioselectivities under very mild conditions. In addition, the reaction features wide substrate scope and good functional group tolerance. Moreover, the trifluoromethylalkynylated products can be easily converted into synthetically useful chiral terminal alkynes, allenes, Z-alkenes, as well as CF3-modified nonsteroidal anti-inflammatory drugs.