Synthesis of o-substituted phenols by Criegee rearrangement of benzylic hydroperoxides

Abstract

9-Phenylthioxanthen-9-ol, 10,10-dimethyl-9-phenyl-9,10-dihydroanthracen-9-ol, and 9-arylfluoren-9-ols undergo Criegee-type rearrangements when treated with hydrogen peroxide and acid to generate substituted benzophenones from the first two substrates, and monoesters of biphenyl-2,2′-diol from the fluorenes via subsequent Bayer-Villiger oxidation of the intermediate 2′-aroylbiphenyl-2-ol. 5-Phenyl-10, 11-dihydrodibenzocyclohepten-5-ol and its dehydroderivative gave the corresponding heptanone and heptenone on treatment with acid and hydrogen peroxide. Prolonged reaction of the 5-phenyldibenzohepten-5-ol afforded products arising from oxidation of the double bond.