X=Y-ZH SYSTEMS AS POTENTIAL 1,3-DIPOLES. PART 13 PROTOTROPIC GENERATION OF AZOMETHINE IMINES FROM HYDRAZONES

Article abstract of DOI:10.1016/S0040-4020(01)87793-0

Hydrazones of aldehydes and ketones undergo to intermolecular cycloaddition to electronnegative olefins via azomethine imines, formed by a formal 1,2-prototropic shift, in low to moderate yield on heating in xylene or ethanol.In some instances the reaction is diverted to give products derived (at least formally) from an ene reaction.Similar intramolecular cycloadditions occur with unactivated terminal alkenes and alkynes.