Disclosed are a new method for synthesizing 7-membered fused heterocycles and compounds synthesized by the new method. The method involves a dual activation strategy using an N-heterocyclic carbene catalyst as a first Lewis base and another second Lewis base. Compounds synthesized by the disclosed method may include new benzoxopinone compounds, as well as benzoxepane compounds and benzoazepinone compounds that optionally may be derived from the disclosed benzoxopinone compounds.