BENZO-RING DIOL EPOXIDES OF BENZO[E]PYRENE AND TRIPHENYLENE

Summary: Synthesis and isolation of the first examples of conformationally rigid, diastereomeric pairs of diol epoxides from trans-dihydrodiols are described. Direct epoxidation of the bay-region benzo[e]pyrene 9, 10-di-hydrodiol and triphenylene 1, 2-dihydrodiolproduces ca. 1:1 mixtures of diastereomeric diol epoxides in which the benzylic hydroxyl group is either cis (isomer 1) or trans (isomer 2) to the epoxide oxygen. Relative stereochemistry is assigned through spectral methods, solvolysis to tetraols, and an alternate route of synthesis. Sir: The bay-region theory1 predicted that benzo-ring diol epoxides of polycyclic aromatic hydrocarbons, in which the epoxide group forms part of a bay region, should be among the chemically most reactive and presumably most biologically active metabolites of a given hydrocarbon. Evidence has beenforthcoming which indicates that this is indeed the case for the eight hydrocarbons which have since been adequately studied.2 For diol epoxides of benzo-ring trans-dihydrodiols, two diastereomers are possible in which the benzylic hydroxyl groupis either cis (isomer 1) or trans (isomer 2) to the epoxide oxygen. © 1979, American Chemical Society. All rights reserved.