Upon oxidation in aprotic media, β-tocopherol (2) forms a spiro-dimer (10) as the main product. The reaction mechanism is a hetero-Diels–Alder process with inverse electron demand of two intermediate ortho-quinone methide molecules. The spiro-dimer can be reduced to the corresponding symmetric ethano-dimer (11). In contrast to the well-studied α-tocopherol case, spiro-dimer and ethano-dimer do not