Spin Adducts in Photolysis of Mixed Benzoyl Phosphonium‒Iodonium Ylide in Dichloromethane

Mixed phosphonium-iodonium ylides are of interest as reactants for the synthesis of new heterocyclic compounds. Recently it has been shown that under irradiation the reactions of phosphonium-iodonium ylides occur with the formation of radicals. The radicals generated in the photolysis of the ylide itself and its fragments, diphenyliodonium salt and triphenylphosphine, or compounds participating in its reactions, dichloromethane and phenylacetylene, are studied with the use of PBN and DMPO spin traps. The obtained results confirm the radical mechanism of the ylide photodecomposition and have allowed us to specify the composition of the primary radicals generated in the photolysis. The unknown EPR parameters of spin adducts are determined for some radicals.