Vitamin E (α-tocopherol: 1a) and its model compound 2,2,5,7,8-pentamethylchroman-6-ol (1b) were oxygenated in aprotic solvents in the presence of the suspended or solubilized superoxide radial (O₂ˉ) under oxygen atmosphere. The reactions proceeded only slightly under anaerobic conditions. In tetrahydrofuran having potassium superoxide (KO₂) suspended, 1a gave rise to 2a and 3a, and 1b to 2b and 3b. A striking characteristic of the reactions is that in the presence of an excess amount of KO₂, 1 and 3 are quantitatively converted to 2. Labeling experiments show that 3a and 3b are precursors of 2a and 2b, respectively, and that the conversion of 3 to 2 is an acyloin rearrangement. In acetonitrile having KO₂ solubilized with dicyclohexano-18-crown-6, 1a gave rise to 7a, and lb to 4b, 5b, 6b, 7b, 8b, and 9b. A hydroperoxide 10b is a precursor of 4b~9b, and 5b is a precursor of 9b. The reactions are characteristic of epoxidations and recyclizations, in which the hydroperoxide 10 may be a key intermediate. The molecular structures of 2b, 3b, 6b, 7b, 8b, and 9b were confirmed by X-ray crystallographic analysis. These reactions are found to be O₂ˉ-induced oxygenations. Possible reaction pathways for the formation of the products are discussed.