Visible-Light-Promoted Remote C-H Functionalization of o-Diazoniaphenyl Alkyl Sulfones.

Visible-light irradiation of ortho-diazoniaphenyl alkyl sulfones in the presence of Ru(bpy) results in remote Csp-H functionalization. Key mechanistic steps in these processes involve intramolecular hydrogen atom transfer from Csp-H bonds to aryl radicals to generate alkyl/benzyl radicals. Subsequent polar crossover occurs by single-electron oxidation of the alkyl/benzyl radicals to carbenium ions that then intercept nucleophiles. We have developed remote hydroxylations, etherifications, an amidation, and C-C bond formation processes using this strategy.