MECHANISM OF OXIDATION OF α,β-UNSATURATED THIONES BY SINGLET OXYGEN

Article abstract of DOI:10.1016/S0040-4020(01)96589-5

Photo-oxidation of α,β-unsaturated thiones yields the corresponding ketones as the only product.Studies carried out three systems, namely thioketones, α,β-unsaturated thiones and thioketenes, have revealed that there exists a similarity in their mechanism of oxidation.It has been suggested that the thiocarbonyl chromophore is the site of attack by singlet oxygen in α,β-unsaturated thiones and that the adjacent C-C double bond is inert under these conditions.Absence of sulphine during the oxidation of α,β-unsaturated thiones is attributed to the electronic factors operating on the zwitterionic / diradical intermediate.While α,β-unsaturated ketones are poorly reactive, α,β-unsaturated thiones are highly reactive toward singlet oxygen.