Photo-induced Vicinal Difunctionalization of Diaryliodonium Salts to Access Bis(tetraphenylphosphonium) Salts

Vicinal bis(tetraarylphosphonium) salts have scarcely been reported in the literatures. In this study, we demonstrate that visible-light-induced difunctionalization of ortho-trifluoromethylsulfonylated diaryliodonium salts conveniently furnishes symmetric bis(phosphonium) salts without additional catalysts or photo-initiators. Furthermore, this reaction is extended to one-step synthesis of cyclic bis(phosphonium) salts. The methodology establishes a practical platform for the preparation of bis(phosphonium) salts using readily available tertiary phosphines. The bis(tetraarylphosphonium) salts are anticipated to garner wide interest in catalytic and medicinal chemistry.