Silica-Gel Catalyzed Stereoselective Conversion of Dialkyl 2-(Imido-<i>N</i>-YL)-3- (triphenylstibanylidene)succinates to Electron-Poor (<i>Z</i>)-<i>N</i>-Vinylimides in Solvent-Free Conditions
作者:Ali Ramazani、Ebrahim Ahmadi
DOI:10.1080/104265090902787
日期:2005.9.1
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 degrees C in high conversions.