A visible-light-induced alkylsulfonylation/bicyclization cascade of 1,7-enynes with thianthrenium salts

Abstract

We report a visible-light-promoted alkylsulfonylation/bicyclization cascade of 1,7-enynes with thianthrenium salts using DABSO as the SO₂ surrogate. This protocol provides operationally-convenient access to various alkylsulfonated benzo[a]fluoren-5-ones under mild conditions. This method features excellent functional group tolerance, wide substrate scope and high step economy. Mechanistic investigations reveal that the transformation undergoes a radical pathway.