The Diels-Alderreaction of 1,7-, 2,7-, 2,6-, 1,6-dihydroxynaphthalene and 6-bromo-2-naphthol with maleic anhydride was investigated. All of these 2-naphthol derivatives gave exo- and endo-adducts (II and III) except for the bromo-naphthol, from which only endo-adduct was obtained. The assignment of exo or endo configuration was based on lactone formation on NaBH4 reduction possible only from the exo