MgLa mixed oxides as highly active and selective heterogeneous catalysts for Wadsworth–Emmons reactions

• Published in: Applied catalysis. B, Environmental Vol. 55; no. 3; pp. 177 - 183
• Main Authors: Kantam, M.L., Kochkar, H., Clacens, J.-M., Veldurthy, B., Garcia-Ruiz, A., Figueras, F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 10.02.2005; Elsevier
• Subjects: Activated hydrotalcites; Catalysis; Catalysis by solid bases; Chemical Sciences; Fluorinated hydrotalcite; MgLa mixed oxides; Wadsworth–Emmons reaction; Activated hydrotalcites; Catalysis by solid bases; Fluorinated hydrotalcite; MgLa mixed oxides; Wadsworth–Emmons reaction
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2004.07.014

The Wadsworth–Emmons reaction usually run in a stoichiometric mode with a high ratio base/substrate can be achieved catalytically, minimizing the by-products. Diethyl(cyanomethyl)-phosphonate and triethylphosphonoacetate were reacted with different aldehydes on solid bases in batch conditions at 383K. MgLa mixed oxide was found to be an efficient solid base for the selective synthesis of α-, β-unsaturated esters and nitriles with greater than 80% yields, and avoiding Knoevenagel condensation and aldolisation even with aliphatic aldehydes. The catalyst could be recycled once with high activity. The effect of substituents on phenyl ring proves that the reaction proceeds via a base catalysed mechanism with a low charge on intermediate species.