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

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 gamma-lactam derivatives with simple treatment. Mechanistically, the single electron transfer (SET) with excited photocatalyst and subsequent deprotonation of triethylamine generates the key alpha-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.

Automated summary

This study describes a photoredox 1,1-dichloromethylation reaction of alkenes using chloroform as the readily available bulk chemical. The reaction selectively produces a variety of 1,1-dichloroalkane products. The transformation can be carried out on a gram-scale and the obtained products can be easily transformed into diverse gamma-lactam derivatives. The method exhibits specific selectivity, broad substrate scope, and mild reaction conditions, making it highly attractive.