One-electron reduction of methyl(trifluoromethyl)dioxirane by iodide ion. Evidence for an electron-transfer chain reaction mediated by the superoxide ion

Article abstract of DOI:10.1021/ja00048a002

One-electron-transfer processes, triggered by I^- in catalytic amounts, convert methyl(trifluoromethyl)dioxirane (1) into 1,1,1-trifluoropropanone (trifluoroacetone) and dioxygen. It is proposed that the initially formed bis(oxy)methylene radical anion 1′ performs nucleophilic attack at the dioxirane 1, yielding a dimeric radical anion 2′; the latter then fragments into trifluoroacetone and superoxide ion (O₂^?-). The intermediacy of Superoxide ion (the propagator of the electron-transfer chain reaction) is demonstrated by its trapping with either benzoyl chloride or chlorotrimethylsilane. Also, potassium superoxide in catalytic amounts induces the fast and complete conversion of 1 into trifluoroacetone with evolution of dioxygen. The redox reaction between dioxirane 1 and iodide ion in acidic medium yields substantial amounts of hydrogen peroxide, which was detected by the catalase probe.