Reactions of some halogenocyclohexadienones

Abstract

Chlorination of 2,4-, 2,6- and 3,5-di-t-butylphenols gave the chlorocyclohexa-dienones (2a), (10), and (7) and (9), respectively. Base-catalysed methanolysis of the ketones (2a) and (9) produced the rearranged gem-dimethoxycyclohexadienones (5)and (11). Under similar conditions the ketone (7) rearranged to 3,5-di-t-butyl-2,4- dichlorophenol, while (10) was converted into a mixture of 2,6-di-t-butyl-1,4-benzo-quinone and 3,5,3',5'-tetra-t-butyl-4,4'-diphenoquinone. The dibromocyclohexa-dienone (2b) also dimerized in the presence of base, affording a low yield of 2,2'-dihydroxy-3,5,3',5'-tetra-t-butylbiphenyl. The mechanisms of these reactions are discussed.