Electron spin resonance studies. Part 58. The formation and reactions of some aliphatic radical-cations in aqueous solution

Evidence is presented that reaction of Cl2–˙ with vinyl ethers proceeds via the formation of the radical-cations of the parent compounds. These species are not directly detectable by e.s.r., but the spectra of radicals formed in one or more of three further reactions have been characterized. These reactions are hydration, addition to the parent molecule, and deprotonation [e.g., CH2CHOEt+˙(from ethyl vinyl ether) yields the hydroxylated radicals ˙CH(OEt)CH2OH and ˙CH2CH(OH)OEt and the ‘dimer’ radical ˙CH(OEt)CH2CH2CH(OH)OEt]. It has been confirmed that analogous radical-cations are also formed during the reactions of the hydroxyl radical with enol ethers at low pH and by elimination reactions of radicals of the type ˙CH(OR)CH2X (with X = Cl, OH, or OMe). It is shown that furan is an effective spin trap for the radical-cations involved in these reactions.