Atom Transfer Radical Addition to Alkynes and Enynes: A Versatile Gold/Photoredox Approach to Thio-Functionalized Vinylsulfones

An efficient intermolecular atom-transfer addition reaction of alkynes via the combination of visible-light photoredox catalysis and gold catalysis has been developed, affording diverse trifluoromethylthio- and difluoromethylthio-functionalized vinylsulfones with high stereoselectivity in good yields. Thiosulfonylation reaction of enyne can also be realized for constructing functionalized carbo- and hetero-cycles through a radical cascade cyclization process. These reactions proceed through a gold-assisted sulfonyl radical addition pathway.