A general photocatalytic platform for the regio- and stereoselective β-chloroacylation of alkenes and alkynes using a heteroleptic copper(I) complex

Abstract Atom transfer radical addition (ATRA) of aroyl chlorides to access β-chloroacyl derivatives via photoredox catalysis remains hamstrung by the need to use precious iridium photocatalysts and activated alkenes as acceptors. Here we report a unified platform for the regioselective chlorocarbonylation of alkenes via visible-light-mediated ATRA of aroyl chlorides catalysed by a heteroleptic Cu(I) complex featuring extensive substrate scope, scalability and functional group tolerance. In addition, alkynes are amenable substrates, allowing E -selective β-chlorovinyl ketone formation. The synthetic utility of the protocol is demonstrated through the functionalization of complex substrates, post-modifications of the products and the formal synthesis of pharmacologically relevant haloperidol, seratrodast and the naturally occurring piperidine alkaloid (−)-sedamine. This study undergirds the exclusive role of a heteroleptic copper(I) complex, which outperforms homoleptic copper(I) complexes—efficient for many ATRA processes—owing to its longer excited-state lifetime and adaptive ligand environment being tailored for the distinctive mechanistic steps catalysed by Cu(I) and Cu(II) in the title reaction.