Abstract

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylstibine and dialkyl acetylenedicarboxylates, by imides (phthalimide and succinimide) leads to vinyltriphenylstibinium salts, which undergo a Michael addition reaction with a conjugate base to produce dialkyl 2-(imido-N-yl)-3-(triphenylstibanylidene)succinates. Silica gel was found to catalyze the stereoselective conversion of dialkyl 2-(imido-N-yl)-3-(triphenylstibanylidene)succinates to electron-poor (Z)-N-vinylimides in solvent-free conditions at 97°C in high conversions.