Asymmetric Nanocatalysis: N-Heterocyclic Carbenes as Chiral Modifiers of Fe3O4/Pd nanoparticles
✍ Scribed by Dr. Kalluri V. S. Ranganath; Dr. Johannes Kloesges; Dr. Andreas H. Schäfer; Prof. Dr. Frank Glorius
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 359 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0044-8249
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✦ Synopsis
Although asymmetric homogeneous catalysis has been a major focus of academic research over the past decades, only very few catalytic systems have proven suitable for large-scale industrial production. Heterogeneous catalytic systems are favored by industry because of the ease of handling, workup, and purification of products, in addition to the robustness and reusability of the catalyst itself. In order to overcome problems of homogeneous catalytic reactions, many different concepts have been developed to generate chiral heterogeneous catalysts. Nanoparticles (NPs) can be considered a semi-heterogeneous support, as they are readily dispersed in the reaction medium, exhibit an intrinsically high surface area, and display highly accessible surface-bound catalytic sites. Fe 3 O 4 NPs have been increasingly recognized as an attractive support for applications in (asymmetric) [2g, 6] catalysis; these NPs are readily available, robust, and magnetically recoverable (thereby obviating tedious catalyst filtration after the reaction).
N-Heterocyclic carbenes (NHCs) are known to form exceptionally stable complexes with many metals. Consequently, they have emerged as versatile donor ligands in transition-metal catalysis and several highly selective applications in asymmetric catalysis have been reported. However, to the best of our knowledge, the successful use of enantiomerically pure NHCs as chiral modifiers for heterogeneous catalysts has not yet been reported.