Photocatalytic radical addition/bicyclization of 1,7-enynes with N-sulfonylaminopyridinium salts/sulfamoyl chlorides: access to sulfonamide-containing benzo[a]fluoren-5-ones

Abstract

A visible light-induced bicyclization of 1,7-enynes with N-sulfonylaminopyridinium salts/sulfamoyl chlorides has been developed. This protocol features mild and metal-free reaction conditions with a broad substrate scope and excellent functional group tolerance. Further mechanistic studies revealed that a radical pathway was operative in these transformations.