Ligand Scaffold Optimization of a Supramolecular Hydrogenation Catalyst: Analyzing the Influence of Key Structural Subunits on Reactivity and Selectivity
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- 作者：Nathan C. Thacker ; Shin A. Moteki ; James M. Takacs
- 刊名：ACS Catalysis
- 出版年：2012
- 出版时间：December 7, 2012
- 年：2012
- 卷：2
- 期：12
- 页码：2743-2752
- 全文大小：480K
- 年卷期：v.2,no.12(December 7, 2012)
- ISSN：2155-5435
文摘
Results are reported for the catalytic asymmetric hydrogenation of two prototypical substrates with a series of more than 150 closely related supramolecular catalysts differing in only their ligand/catalyst scaffold. These modular catalysts are constructed from four subunits and vary widely in their reactivity (no reaction to quantitative yield) and enantioselectivity (racemic to 96% enantiomeric excess (ee)). Analysis of the ligand/catalyst scaffold optimization data reveals how each subunit contributes to the effectiveness of the modular supramolecular catalyst. The results suggest that a balance between key elements of rigidity and flexibility is required for the successful catalysts and, moreover, that this balance is required to enable effective fine-tuning via catalyst scaffold optimization.