Visible‐Light‐Induced Photoredox 1,1‐Dichloromethylation of Alkenes with Chloroform

Abstract A photoredox 1,1‐dichloromethylation of alkenes with the readily available bulk chemical chloroform was described, furnishing a variety of 1,1‐dichloroalkane products selectively. Furthermore, this transformation could proceed smoothly on gram‐scale, and the obtained products could transform into diverse γ‐lactam derivatives with simple treatment. Mechanistically, the single electron transfer (SET) with excited photocatalyst and subsequent deprotonation of triethylamine generates the key α‐aminoradical intermediate, which enables selective Cl‐atom transfer of chloroform. The specific selectivity, broad substrate scope, as well as the mild reaction conditions make this strategy especially attractive. magnified image