Nickel-Catalyzed Cross-Electrophile Couplings of Tetraarylphosphonium Salts with Aryl Bromides.

We report herein an effective cross-electrophile coupling of tetraarylphosphonium salts with aryl bromides, which proceeded well through C-P bond activation in tetrahydrofuran (THF) with the assistance of a NiCl2 catalyst, Mg turnings, and LiCl. By taking advantage of this coupling strategy, a broad spectrum of structurally diverse biaryls could be conveniently synthesized in moderate to high yields with reasonable functional group tolerance. Scaled-up synthesis and late-stage elaboration of complex molecules were also realized. Preliminary investigations of the reaction mechanism revealed that an arylmagnesium species, which is produced in situ through the oxidative addition of Mg to bromoarene, presumably functions as the key intermediate of the reaction.