Lewis-acid-mediated regioselectivity switching by aromatization-driven rearrangement of 5-amino-1,4-epoxy-1,4-dihydronaphthalenes

Selective synthesis of 8- or 5-amino-substituted 1-naphthols through rearrangement is demonstrated using Lewis acids. A variety of tetrasubstituted 1-naphthols were selectively prepared from 2,4-disubstituted 5-amino-1,4-epoxy-1,4-dihydronaphthalenes in a Lewis-acid-dependent manner with AlCl3 or ZnCl2 serving as the activators. A unique reaction mechanism was proposed on the basis of NMR experiments.