Halophosphonium Salts-Mediated Photochemical C(sp³)–H Functionalization

Herein we report a method that uses halophosphonium salts as dual-function reagents for versatile C(sp³)-H functionalization under visible light. They serve simultaneously as photocatalysts and hydrogen atom transfer reagents, eliminating the need for exogenous metal catalysts. This strategy enables benzylic, allylic, and aliphatic C-H alkylation, hydrazination, and cyanation. The discovery significantly expands the synthetic utility of halophosphonium salts beyond their classical roles, establishing them as modular photochemical scaffolds for green organic synthesis.