Investigation into phenoxonium cations produced during the electrochemical oxidation of chroman-6-ol and dihydrobenzofuran-5-ol substituted compounds

A series of chroman-6-ol and dihydrobenzofuran-5-ol based compounds with structures similar to vitamin E were examined by cyclic voltammetry and controlled potential electrolysis. The compounds displayed characteristic voltammetric features that enabled their electrochemical behavior to be interpreted in relation to the oxidation mechanism for vitamin E. The electrochemical experiments indicated the presence of several oxidized species: cation radicals, phenoxyl radicals, phenoxonium ions, hemiketals, and p-quinones, whose lifetimes varied depending on the extent of methylation of the aromatic ring (R(1), R(2), R(3)) and the nature of substituents R(4) and R(5).