Enantioselective Copper-Catalyzed Intermolecular Cyano­trifluoro­methylation of Alkenes via Radical Process

A novel enantioselective copper-catalyzed intermolecular cyano­trifluoro­methylation of alkenes has been developed, in which a variety of CF3-containing alkylnitriles are furnished with excellent enantiomeric excess. Preliminary mechanistic studies revealed (1) the reaction was initiated by a SET process between activated Togni’s CF3+ reagent and a Cu­(I) catalyst; (2) the released CF3 radical readily added to styrene to provide a benzylic radical, which was then trapped by a chiral Cu­(II) cyanide species to deliver the desired alkylnitriles; (3) a low concentration of the CN anion was crucial to obtain high enantioselectivity.