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

Abstract

We describe a Re 2 O 7 -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.N itrogen-containing heterocycles (N-heterocycles) are, arguably, one of the most important organic structures, which are frequently seen in dyes, agrochemicals, and pharmaceuticals. 1,2 Tetrahydrobenzo[d]azepines are benzofused N-heterocycles that have been found in various natural products and biologically active compounds (Figure 1). 3−9