3, 6-Dimethoxybenzocyclobutenone 4 is prepared in four efficient steps from 2, 5- dimethoxybenzoic acid 8. The derived benzocyclobutenol 13 undergoes electrocyclic ring opening at 110–115° C to give the hydroxy-o-quinone dimethide 21, which reacts with dienophiles to give 5, 8-dimethoxy-1, 2, 3, 4-tetrahydro-1-naphthol derivadves stereoselecdvely. Since the ketone 4 can be functionalised at C-5 using electrophiles and ...
