Route to Functionalized Tetrahydrobenzo[d]azepines via Re2O7-Mediated Intramolecular Friedel–Crafts Reaction

We describe a Re2O7-mediated intramolecular dehydrative Friedel–Crafts reaction for the efficient synthesis of various benzo-fused heterocycles such as benzazepines and benzazocines. This process is characterized by a broad substrate scope, mild reaction conditions, high efficiency, and high atom economy. The potential application of this methodology was exemplified by the facile preparation of a NMDA antagonist as well as a key intermediate en route to SKF 38393.