Practical Synthesis of Functionalized Chromeno[3,4-c]pyridine Derivatives via a CuCl2-Catalyzed Tandem Reaction of the Blaise Reaction Intermediates and 3-Cyanocoumarins

Abstract

This work discloses a novel and efficient protocol for the construction of functionalized chromeno[3,4-c]pyridine derivatives from the Blaise reaction intermediates and 3-cyanocoumarins through a CuCl2-catalyzed sequential Michael addition/intramolecular cyclization/oxidative aromatization reaction. This new method shows the advantages of mild reaction conditions, easy workup, nonchromatographic purification technique, good functional group tolerance, and moderate to good yields.