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. (Figure presented.).