Visible-light photoredox-catalyzed dual C-C bond cleavage: synthesis of 2-cyanoalkylsulfonylated 3,4-dihydronaphthalenes through the insertion of sulfur dioxide.

An efficient novel visible-light photoredox-catalyzed dual carbon-carbon bond cleavage of methylenecyclopropanes and cycloketone oximes for the synthesis of 2-cyanoalkylsulfonated 3,4-dihydronaphthalenes through the insertion of sulfur dioxide is established. This dual cleavage of carbon-carbon bonds involves a radical pathway and goes through a sequence of iminyl radical formation, carbon-carbon bond cleavage, sulfur dioxide insertion, sulfonyl radical addition, another carbon-carbon bond cleavage, and intramolecular cyclization.