Financial support from the Irish Research Council for Science Engineering and Technology is gratefully acknowledged. We would like to thank TopChem Laboratories Ltd. and the Gunnlaugsson group (TCD) for the use of their equipment.
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Communication
Urea- and Thiourea-Substituted Cinchona Alkaloid Derivatives as Highly Efficient Bifunctional Organocatalysts for the Asymmetric Addition of Malonate to Nitroalkenes: Inversion of Configuration at C9 Dramatically Improves Catalyst Performance.†
Article first published online: 1 SEP 2005
DOI: 10.1002/anie.200501721
Copyright © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Additional Information
How to Cite
McCooey, S. H. and Connon, S. J. (2005), Urea- and Thiourea-Substituted Cinchona Alkaloid Derivatives as Highly Efficient Bifunctional Organocatalysts for the Asymmetric Addition of Malonate to Nitroalkenes: Inversion of Configuration at C9 Dramatically Improves Catalyst Performance.Angewandte Chemie International Edition, 44: 6367–6370. doi: 10.1002/anie.200501721
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Publication History
- Issue published online: 30 SEP 2005
- Article first published online: 1 SEP 2005
- Manuscript Received: 19 MAY 2005
Keywords:
- asymmetric catalysis;
- cinchona alkaloids;
- Michael addition;
- organocatalysis;
- ureas
Graphical Abstract
Natural not always best: Novel N-aryl urea and thiourea derivatives of dihydrocinchona alkaloids serve as efficient catalysts for the asymmetric addition of dimethyl malonate to a range of nitroalkenes. Catalytic activity and selectivity depend strongly on the relative configuration at C8/C9. Catalysts with “non-natural” inverted configuration at C9 display excellent activity and enantioselectivity at loadings as low as 0.5 mol %.