Photocatalytic anti-Markovnikov Chloroalkynylation of Unactivated Alkenes

A photoinduced three-component anti-Markovnikov chloroalkynylation of unactivated alkenes is enabled by proton-coupled electron transfer (PCET) using bench-stable HCl and alkynyl sulfones. A neutral acridine photocatalyst promotes cascade radical addition/fragmentation under mild conditions, delivering highly regioselective products otherwise difficult to access. The method accommodates diverse unactivated alkenes, including alkyl-substituted, 1,1-disubstituted, and drug-like derivatives. Diverse downstream derivatizations highlight the synthetic utility of these chloroalkyne building blocks.