Construction of Bisbenzopyrone via N-Heterocyclic Carbene Catalyzed Intramolecular Hydroacylation-Stetter Reaction Cascade.

An efficient synthesis of bisbenzopyrones by a N-heterocyclic carbene (NHC)-catalyzed intramolecular hydroacylation-Stetter reaction cascade has been developed. A series of symmetrical and unsymmetrical bisbenzopyrones were obtained with good to excellent yields. Bisbenzopyran-4-ol was synthesized efficiently.