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 heterocycles through a
radical cascade cyclization process. These reactions proceed through
a gold-assisted sulfonyl radical addition pathway.