Photochemistry and Photophysics of Aromatic Sulfoxides. 3. α-Cleavage and the Role of the Sulfenic Ester

Article abstract of DOI:10.1021/jo00122a029

The photochemistry of aryl benzyl sulfoxides is described.The initial event is homolytic cleavage to form a singlet sulfinyl/benzyl radical pair.The radical pair partitions between reversion to starting material with at least partial racemization and closure to form a sulfenic ester.With acetone sensitization, the primary radical pair also undergoes quite significant escape, leading to formation of diphenylethane and aryl arenethiosulfonates.Secondary photolysis of the sulfenic ester leads exclusively to S-O homolysis, yielding the radical pair from which isolated products are derived.Quantum yields and other mechanistic observations are discussed.