Regiocontrolled Annulation of Benzocyclobutenols with Alkynes.

A tandem reaction that involves an unprecedented Rh-catalyzed intramolecular annulation of benzocyclobutenols with alkynes and subsequent ZnCl 2 -promoted dehydration was developed, offering an efficient approach to 2 H -furan-, pyran-, and oxepine-fused naphthalenes. Furthermore, the 2 H -furan motif may undergo a ring-opening reaction through Fe-catalyzed reductive C-O bond cleavage. As a consequence, the formal intermolecular annulation of 2-hydroxybenzocyclobutenols with alkynes was realized with complete regioselectivity through a two-step protocol.