The preparation of diastereomeric anti-and syn-epoxides of benzoli] fluoranthene (BjF) 4, s and 9, lodihydrodiols is described. The anti-diol epoxides were prepared from the corresponding dihydrodiols by epoxidation with m-chloroperoxybenzoic acid. The isomeric syn-diol epoxides were synthesized by base-catalyzed (Amberlyte IRA-400) cyclization of the bromo triol derivatives which in turn were prepared from the respective dihydrodiols by ...