Visible light-mediated stereoselective haloalkylation of bicyclic alkenes

Abstract

The atom transfer radical addition (ATRA) of alkyl halides enables efficient simultaneous C–C and C–halogen bond formation in a single step. However, the development of mild, cost-effective ATRA protocols for the reaction of bicyclic alkenes with functionalized haloalkanes remains a significant challenge and underexplored. Herein, we report visible-light-mediated ATRA haloalkylation of bicyclic alkenes using functionalized haloalkanes. This catalytic system operates under mild and peroxide-free conditions, enabling the construction of haloalkylated bicyclic frameworks in a complete atom-economy across diverse substrates with generally good stereoselectivities. Scalability studies and downstream derivatizations of the products underscore the synthetic utility of the present haloalkylation protocol. Additionally, mechanistic studies including in-depth DFT calculations, have clarified the reaction pathway and origin of stereoselectivity.