Direct C─H Arylation of (Hetero)arenes Using Hantzsch Ester as a Photoredox Catalyst

Abstract

An efficient method for visible-light-initiated direct C─H arylation of unactivated arenes and N-methylpyrrole with aryl halides using diethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (HEH) as a photoredox catalyst without a sacrificial reductant has been developed. The reaction design enables single-electron reduction of aryl halides upon the photoexcitation of HE⁻, and the resulting aryl radicals undergo aryl-(hetero)aryl cross-coupling. This transformation tolerates a wide range of functional groups, is convenient to perform on a gram scale, and is suitable for late-stage functionalization of complex molecules.