Light-promoted, nickel-catalyzed C–N coupling of (hetero)aryl halides with benzophenone hydrazone for the synthesis of nitrogen-containing heterocycles

Abstract

A highly effective C–N coupling reaction of (hetero)aryl halides with benzophenone hydrazone is reported. Catalyzed by a Ni(II)–aryl halide complex under UV irradiation (390–395 nm) in the presence of a soluble amine base without the need for an external photosensitizer, these reactions provide convenient, potentially scalable access to synthetically important N-arylhydrazones. We demonstrated the robustness of the method by synthesizing indoles, N-arylpyrazoles, triazolopyridines, triazoloquinolines, and furoindolines via coupling reactions and subsequent in situ hydrolysis/cyclization in the same pot.