Bimolecular photoreduction of aromatic sulfoxides

Photolysis of aromatic sulfoxides in the presence of alkoxides in alcoholic solvents provides a photochemical route to the corresponding sulfides. Oth er electron donors also give sulfide with various degrees of success. The r eaction could also be carried out using carbazoles as sensitizers, and quan titative yields could be obtained using N-methylcarbazole in methanol. Evid ence points toward a hydroxysulfuranyl radical as the key intermediate, and solvent effects point to heterolysis, rather than homolysis, as the step t hat breaks the S-O bond.