MeOTf-catalyzed formal [4 + 2] annulations of styrene oxides with alkynes leading to polysubstituted naphthalenes through sequential electrophilic cyclization/ring expansion

MeOTf-catalyzed formal [4 + 2] annulation of styrene oxides with alkynes to afford polysubstituted naphthalenes has been realized, which undergoes sequential electrophilic cyclization/ring expansion. A range of substrates were tolerated in the formation of naphthalene derivatives with high regioselectivity in satisfactory yields. The reaction could also be carried out on gram scale.