Photolysis of N-acyl-SS-diphenylsulphimides

Abstract

Photolysis of the N-acyl-SS-diphenylsulphimides (Ia–e) in benzene or tetrahydrofuran gave the corresponding isocyanates (IIa–e), biphenyl, diphenyl sulphide, diphenyl disulphide, and/or urea derivatives (IIIa and b). The yields of isocyanates (IIa–e) were as high as those attained in the photolysis of the corresponding azide derivatives. The formation of the isocyanates is explained in terms of a photo-Curtius rearrangement of an acylnitrene, formed photochemically by cleavage of the sulphur–nitrogen bond. The mode of formation of the urea derivatives (IIIa and b) is also discussed.