Amine-Ligated Boryl Radical-Enabled Hydrofunctionalization of Styrenes via Halogen-Atom Transfer of Alkyl and Aryl Bromides

Herein, we demonstrate amine-ligated boryl radical-mediated halogen-atom transfer (XAT) strategy with alkyl and aryl bromides to construct C(sp3)–C(sp3) and C(sp3)–C(sp2) bonds, respectively. The first step involves the photocatalytic and decarboxylative generation of amine-ligated boryl radicals from a carboxylic acid containing amine-ligated borane. The resulting amine-ligated boryl radical undergoes XAT with organobromides to generate carbon-centered radicals, which react with styrenes to afford hydrofunctionalized products. Furthermore, this photocatalytic XAT strategy can be applied to synthesize gem-difluorostyrene and 1,1-disubstituted cyclopropane through a radical-polar crossover mechanism.