Directable regiochemistry in naphthazarins via the use of masked derivatives

Article abstract of DOI:10.1016/0040-4039(93)89004-A

The carboethoxynaphthol 3d was converted via salcomine oxidation to the masked carboethoxynaphthazarin 4b which could undergo nucleophilic addition or, if unmasked, transfer quinone reactivity to the alternative ring in form 5. The latter should undergo regiospecific Diels-Alder reactions.