Photochemical Ni-Catalyzed Selective Mono-N-Arylation

Abstract

The selective synthesis of N-monomethyl arylamines presents an important challenge in synthetic chemistry. Furthermore, small molecule amines readily coordinate with metal catalysts, causing catalyst deactivation. In this work, we report an efficient C–N coupling reaction of (hetero)aryl halides with small molecule amine salts. Without the need for an external photosensitizer in the presence of a soluble organic base, a bipyridine-Ni(II) complex serving as a catalyst successfully enables the selective C–N coupling of (hetero)aryl halides with methylamine, deuterated methylamine, ethylamine, and dimethylamine under purple light irradiation (390–395 nm), thus preventing catalyst deactivation. Mechanistic studies reveal that the reaction proceeds via a Ni(I)–Ni(III) catalytic cycle, and more than 100 examples showcase its feasibility and versatility in organic synthesis.