Synthesis of imidazo[1,2- a ]benzoazepines by alkyne-carbonyl-metathesis.

Imidazo[1,2- a ]benzoazepines were prepared by Brønsted acid-mediated intramolecular alkyne-carbonyl metathesis (ACM). The starting materials, imidazole and benzimidazole derivatives, were prepared by N -alkylation, formylation and Sonogashira cross-coupling reaction. The final intramolecular ACM delivered the final products in good to excellent yields and with a wide tolerance towards functional groups.