Organocatalytic Synthesis of Spiro-Bridged Heterocyclic Compounds via a Chemoselective Vinylogous Michael/Cyclization/Rearrangement Sequence

An organocatalytic cascade reaction of 2-ethylidene 1,3-indandiones and isatylidene-malononitriles has been achieved using quinine as the catalyst. The unexpected vinylogous Michael addition at the β position of isatylidene-malononitriles, followed by aldol cyclization, 1,2-addition of alkoxide to nitrile, and [1,3]-O-to-N rearrangement, leads to the generation of unique spiro-bridged heterocyclic compounds containing amide, indanone, and oxindole moieties in good to excellent yields with high diastereoselectivity.