Silica-Gel Catalyzed Stereoselective Conversion of Dialkyl 2-(Imido-N-YL)-3- (triphenylstibanylidene)succinates to Electron-Poor (Z)-N-Vinylimides in Solvent-Free Conditions

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.

Keywords:

• Stibine ylide
• silica gel
• (Z)-N-vinylimide
• solvent-free conditions
• catalyst

Acknowledgments

This work was supported by the Zanjan University.