Copper-Catalyzed Trifluoromethylation of Alkyl Bromides

Copper oxidative addition into organohalides is a challenging two-electron process. In contrast, formal oxidative addition of copper to C_sp² carbon–bromine bonds can be accomplished by employing latent silyl radicals under photoredox conditions. This novel paradigm for copper oxidative addition has now been applied to a Cu-catalyzed cross-coupling of C_sp³-bromides. Specifically, a copper/photoredox dual catalytic system for the coupling of alkyl bromides with trifluoromethyl groups is presented. This operationally simple and robust protocol successfully converts a variety of alkyl, allyl, benzyl, and heterobenzyl bromides into the corresponding alkyl trifluoromethanes.