Preparation of Fullerendione through Oxidation of Vicinal Fullerendiol and Intramolecular Coupling of the Dione To Form Hemiketal/Ketal Moieties

Vicinal fullerendiol is oxidized to fullerendione in good yield by (diacetoxy)iodobenzene. The resulting cage-opened fullerendione reacts with oxygen nucleophiles in the presence of BF3·Et2O to form fullerene hemiketal/ketal derivatives through coupling of the two carbonyl groups. Fullerene-mixed peroxide derivatives are involved in all these reactions. The compounds are characterized by spectroscopic data and single-crystal X-ray analysis.