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.