N-PROTONATED AZOMETHINE YLIDES WITH A LEAVING GROUP AS SYNTHETIC EQUIVALENTS FOR NONSTABILIZED NITRILE YLIDES

Abstract
Through alkylation or silylation and then desilylation steps, N-(silylmethyl)amidines generate N-protonated azomethine ylides which cycloadd to olefins, acetylenes, and aldehydes giving 1- or 2-pyrrolines, pyrroles, and 2-oxazolines, respectively, after the elimination of N-substituted anilines. With this sequence, the amidines are useful synthetic equivalents of nonstabilized nitrile ylides.