Selective α-oxidation of amides via visible-light-driven iron catalysis

Hydroxyl radicals ((OH)-O-center dot) as one of the highly reactive species can react unselectively with a wide range of chemicals. The (OH)-O-center dot radicals are typically generated under harsh conditions. Herein, we report hydroxyl radical-induced selective N-alpha C(sp(3))-H bond oxidation of amides under greener and mild conditions via an Fe(NO3)(3)<middle dot>9H(2)O catalyst inner sphere pathway upon irradiation with a 30 W blue LED light strip (lambda = 455 nm) using NaBrO3 as the oxidant. This protocol exhibited high chemoselectivity and excellent functional group tolerance. A preliminary mechanism investigation demonstrated that the iron catalyst afforded hydroxyl radicals via the visible-light-induced homolysis (VLIH) of iron complexes followed by a hydrogen atom transfer (HAT) process to realize this transformation.