Benzylamine promoted direct C-H arylation of arenes and heteroarenes via excitation with heat or light.

Abstract

Carbon-halogen bond cleavage in aryl halides through single electron transfer (SET) is a crucial step in radical-based cross-coupling reactions. Accomplishing such cleavage using an organic system without the assistance of any transition metal-based catalyst is highly challenging. In recent years, combining organic molecules and a base has served as a unique system for SET-mediated carbon-halogen bond cleavage. Herein, we report the combination of simple benzylamine and potassium tert-butoxide as a super-electron-donor system for SET-mediated cleavage of aryl halides generating reactive aryl radicals, which subsequently react with arenes or heteroarenes and produce biaryl skeletons. The new methodology enables the arylation of arenes and heteroarenes with aryl iodides, or aryl bromides, upon excitation with heat or light. The broad substrate scope, mild reaction conditions and tolerance of common organic functional groups offer an efficient alternative route for direct C-H arylation reactions.