Synthesis of Ketone and Alcohol Derivatives of Methylene-Bridged Polyarenes, Potentially New Classes of Active Metabolites of Carcinogenic Hydrocarbons

Article abstract of DOI:10.1021/jo00049a045

Methods for the syntheses of bridge ketone and alcohol derivatives of methylene-bridged polyarenes from the parent hydrocarbons are described.The polyarenes investigated include 4H-cyclopentaphenanthrene (1a), fluorene (2a), 7H-benzofluorene (3a), 4H-cyclopentachrysene (4a), 11H-benzaceanthrylene (5a), 10H-indeno<1,2,7,7a-bcd>pyrene (6a), 11H-dibenzoaceanthrylene (7a), 4H-fluoreno<4,4a,4b,5-abc>anthracene (8a), and 7H-dibenzofluorene (9a).The bridge ketone derivatives are most efficiently synthesized via treatment of the parent hydrocarbons with n-butyllithium and reaction of the resulting anionic intermediate s with molecular oxygen.The direct formation of ketones rather than the expected hydroperoxides from reaction of the bridge anions with O2 presumably involves intra- or intermolecular abstraction of a proton from the benzylic site of the intermediate by the peroxy anion leading to loss of hydroxide ion with formation of a carbonyl group.Yields are generally high except in the cases of 1a and 4a; the former affords as the principal product a dimeric alcohol arising from reaction of the anion of 1a with the corresponding ketone 1b.The related bridge alcohols are readily obtained in yields of 75-95percent by reduction of the crude products from the preceding oxidations with NaBH4.