N-Heterocyclic carbene-catalyzed three-component domino reaction of alkynyl aldehydes with oxindoles.

A new and stereoselective synthetic approach to spirooxindole 4H-pran-2-one derivatives with three contiguous stereogenic centers has been developed via an NHC-catalyzed three-component domino reaction of alkynyl aldehydes with oxindoles. The reaction proceeds smoothly in good yields with good to high diastereoselectivities. These novel heterocyclic spirooxindoles may provide promising candidates for drug discovery. Additionally, a possible mechanism for the entire reaction sequence is proposed.