A New and General Route to N-Protonated Azomethine Ylides from N-(Silylmethyl)amidines and -thioamides. Cycloaddition of Synthetic Equivalents of Nitrile Ylides

Article abstract of DOI:10.1021/jo00361a012

The N- or S-alkylation or -silylation of N-(silylmethyl)amidines or -thioamides and the subsequent desilylation of the silylmethyl group generate N-protonated azomethine ylides bearing a leaving group.These azomethine ylides undergo successful cycloaddition with electron-deficient olefins, acetylenes, and aldehydes.As the leaving group is eliminated under the reaction conditions, these azomethine ylides can be synthetic equivalents of nonstabilized nitrile ylides which are otherwise relatively inaccessible.