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.