Catalyst-Free Photoinduced ortho C–H Heteroarylation of Phenols

Visible-light-induced ortho C–H heteroarylation of free phenols with heteroaryl halides in the absence of both transition-metal and photoredox catalysts has been developed. This reaction proceeds through single-electron transfer of the excited charge-transfer complex between the pyridine substrate and t BuONa, followed by addition to the phenol. This heteroarylation was tolerant toward diverse functional groups and has been demonstrated with a gram-scale reaction.