SYNTHESIS OF PHENYL SUBSTITUTED CYCLOHEXA-1,4-DIENES AND CYCLOHEXA-2,5-DIENONES BY ANODIC METHOXYLATION OF ALKYLBIPHENYLS

The anodic methoxylation of a series of alkylbiphenyls (2-, 3-, 4-methylbiphenyl, 3,3'-, 4,4'-dimethylhiphenyl, 4-ethylhiphenyl and 4,4'-di-tert-butylbiphenyl) carried out under constant current intensity afforded, in a process of two electrons, a number of cis/trans cyclohexa-1,4-dienes and, in a process of four electrons, a number of cyclohexa-2,5-dienones after acidic hydrolysis of the corresponding cyclohexa-l,4-diene ketals. In some cases, side-chain substitution products were also obtained. Probable mechanisms are proposed. © 1990.