Oxidation of alkoxyphenols. XXIX phototautomerism and dimerization of 4,6-Di-t-butyl-4a-hydroxy-8-methoxy-dibenzofuran-2(4aH)-one

In solution in non-polar solvents the title compound undergoes photochemical ring opening to its hydroxyphenylquinone tautomer. Oxidation of 3,3′-di-t-butyl-5,5′-dimethoxybiphenyl-2,2′-diol with vanadium oxytrifluoride in the presence of trifluoroacetic acid yields bisdibenzofurans. The crystal structures of 4,4′,6,6′-tetra-t-butyl-2′,8-dimethoxy-1,1′-bisdibenzofuran-2,8′-diol and of 4,6-di-t-butyl-4a-hydroxy-8-methoxydibenzofuran-2(4aH)-one have been determined.