The syntheses of 7a, 15a-dlhydro-15a-methylnaphtho [2, lb] naphtho [1', 2': 5, 6] pyrano [3, 2- e] pyran (II) and 7a, 15a-dihydro-7a-methyl-15a-isopropyi naphtho [2, 1-b] naphtho [1', 2': 5, 6] pyrano [3, 2-e] pyran (III) from 2-naphthol and corresponding dimethylol ketones in one step were described. Amberlyst-15® was used as catalyst.
