Absolute structure of catalponol, a naphthoquinone congener of Catalpa ovata has been established as 1. Examination of the reaction of 1 and its oxidation product, catalponone (2) with BF3 giving several derivatives including natural products such as 2, 2-dimethylnaph-thochroman (12), nordihydrolapachenole (14) and tetrahydrotectol (15), has offered interesting materials for considering the biosynthetic pathway of these substances.
