454232 Base-Free Knoevenagel Condensation Catalyzed By Different Heterogeneous Copper Catalysts

Wednesday, November 16, 2016
Grand Ballroom B (Hilton San Francisco Union Square)
Elia Schneider1, Martin Zeltner2, Robert N. Grass3 and Wendelin J. Stark3, (1)ETH Zurich Institute for Chemical and Bioengineering, ETH Zurich, Zurich, (2)ETH Zurich, 8093 Zurich, Switzerland, (3)Institute for Chemical and Bioengineering, ETH-Zürich, Zürich, Switzerland

The famous Knoevenagel condensation is a widely used reaction in research and industry and has been of importance for several pharmaceutical products. Generally this reaction is catalyzed by organo-bases, such as pyridine or piperidine, but using these homogeneous base catalysts often leads to time consuming work-up procedures. Heterogeneous catalysts would solve such a problem. Therefore, we explored different nanomaterials which might catalyze this reaction. This lead to the discovery of copper as a reative species.

For the first time the Knoevenagel condensation was catalyzed by different forms of elemental copper with high activity and excellent isolated yields. Different sizes & surface functionalities of copper nanoparticles showed different conversion rates. Carbon-coated copper nanoparticles showed low conversion whereas naked, comercially available copper nanoparticles exhibited high activity. It was assumed that the reduced copper surface is the active catalytic site. A succesful scale up (>100 g) reaction was performed without any separation or chormatography resulting in 91 % isolated yield .

Schneider, E.M; Zeltner M.; Kraenzlin N.; Grass R. N.; Stark W. J. Chem. Commun., 2015,51, 10695-10698

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