Regiocontrolled Annulation of Benzocyclobutenols with Alkynes

A tandem reaction that involves an unprecedented Rh-catalyzed intramolecular annulation of benzocyclobutenols with alkynes and subsequent ZnCl2-promoted dehydration was developed, offering an efficient approach to 2H-furan-, pyran-, and oxepine-fused naphthalenes. Furthermore, the 2H-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.

Automated summary

This tandem reaction involves Rh-catalyzed intramolecular annulation of benzocyclobutenols with alkynes followed by ZnCl2-promoted dehydration, providing an efficient strategy for the synthesis of 2H-furan, pyran, and oxepine-fused naphthalenes. The 2H-furan motif can also undergo a ring-opening reaction through Fe-catalyzed reductive C-O bond cleavage, enabling the formal intermolecular annulation of 2-hydroxybenzocyclobutenols with alkynes with complete regioselectivity in a two-step protocol.