Copper- and Photoredox-Catalyzed Cascade to Trifluoromethylated Divinyl Sulfones

A Cu(I)-photoredox-catalyzed trifluoromethylchlorosulfonylation reaction of terminal alkynes under visible light conditions was developed, giving rise to trifluoromethyl-substituted vinylsulfonyl chlorides, which can subsequently be coupled to a second alkyne under photocatalytic conditions. The transformation proceeds with high regio- and stereoselectivity and can be applied to aliphatic and aromatic alkynes with various functional groups. Trifluoromethyl-substituted divinyl sulfones prepared by this protocol can be readily used as synthetically valuable intermediates as demonstrated with various postmodification examples.