[Total synthesis of an analogue of schizandrin]

A schizandrin analogue 9, 1, 2, 3, 10, 11, 12-hexamethoxy-6,7-dihydroxy-cis-6,7-dimethyl dibenzocyclooctadiene, is one of the metabolites of schizandrin with comparable anti-convulsion activity. In this paper, compound 9 was synthesized from gallic acid through the following sequence of reactions: methylation, Henry condensation, reduction with Fe-FeCl3-HCl, intermolecular reductive coupling and intramolecular nonphenolic oxidative coupling, totally in seven steps. The intermediate 1,4-diaryl-2,3-dimethyl-2,3-butanediol (7) which is a mixture of erythro and threo isomers was converted by DDQ in TFA into compound 9 and another new compound 10 via a different reaction path.