Efficient Synthesis of Benzofuranones: N-Heterocyclic Carbene (NHC)/Base-Catalyzed Hydroacylation-Stetter-Rearrangement Cascade

A N-heterocyclic carbene/base-catalyzed cascade reaction leading to the formation of functionalized benzofuranones is reported. The reaction proceeds via an intramolecular hydroacylation of unactivated alkynes followed by an intermolecular Stetter reaction and a base-catalyzed chromanone to benzofuranone rearrangement.