Photo-induced 1,2-carbohalofunctionalization of C–C multiple bonds via ATRA pathway

Abstract

Radical vicinal carbohalofunctionalization of C–C multiple bonds via atom transfer processes constitutes an efficient method for the construction of halogenated building blocks with complete atom economy via radical cleavage of a pre-existing carbon–halogen σ-bond of an atom transfer reagent and their transposition over the π-bond of alkenes and alkynes. This review summarizes the recent advances in the photo-induced version of this class of transformations. A variety of transition-metal complexes, organic dyes, phosphines, amines, phenols and aldehydes were utilized as catalysts for the cleavage of the existing carbon–halogen bond of the corresponding atom transfer reagent in the presence of a light source. Alongside a variety of 1,2-haloalkylation and haloperfluoroalkylation reactions, atom transfer radical addition (ATRA) or cyclization (ATRC) reactions via the cleavage of the carbon–halogen bonds of aryl halides are also discussed.