Photo-induced transformation of α-diazocarbonyl compounds into mono-substituted alpha-halogen derivatives

Herein, the hydrogen halogenation reaction of diazo compounds with three new halogenating agents under photoinduced conditions is reported. This method realized hydrofluorination, hydrochlorination, and hydrobromination (56 cases in total, with the highest preparative yield of 94%) without requiring heating, transition metal catalysts or photocatalysts and exhibits a broad substrate scope. Notably, gram-scale synthesis using a continuous flow reactor was performed.