Indole-fused 1,4-diazepines are found in various biologycally active compounds and can be considered as an attractive drug template. We recently reported a novel copper(I)-catalyzed synthesis of 2-(aminomethyl)indoles by a three-component coupling–cyclization reaction. This reaction prompted us to develop a new method for the preparation of indole-fused 1,4-diazepines by three-component indole formation and simultaneous copper-catalyzed N-arylation. Starting from simple 2-ethynylanilines and o-bromobenzylamines, complex indole-fused tetracyclic compounds including 1,4-benzodiazepines were easily and directly constructed in a single reaction vessel. This is the first example of copper-catalyzed one-pot reaction including three catalytic cycles and formation of four bonds.
