Molecular-Iodine-Promoted Synthesis of Dihydrobenzofuran-3,3-dicarbonitriles through a Novel Rearrangement

Abstract

The title compounds were synthesized from 5,5-dimethyl­cyclohexane-1,3-dione, benzaldehyde, and malononitrile promoted by molecular iodine in basic medium via 2-amino-7,7-dimethyl-5-oxo-4-phenyl-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile, by a novel protocol. The protocol involves a novel rearrangement in which the 4H-chromene fragment dissociates to a cyclopropane moiety and rearranges to the five-membered compound 6,6-dimethyl-4-oxo-2-phenyl-4,5,6,7-tetrahydrobenzofuran-3,3(2H)-dicarbonitrile. Simple reaction conditions, excellent yields, and high compatibility are the advantages of this protocol.