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 Csp2 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 Csp3-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.