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Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
Published on: January 17, 2020
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Asymmetric catalysis with a chiral-at-osmium complex
Guanghui Wang1, Zijun Zhou1, Xiang Shen1
1Fachbereich Chemie, Philipps-Universitat Marburg, Hans-Meerwein-Strasse 4, 35043 Marburg, Germany. meggers@chemie.uni-marburg.de.
Chemical Communications (Cambridge, England)
|June 16, 2020
Summary
Researchers developed a novel chiral osmium catalyst with metal-centered chirality. This catalyst enables enantioselective C(sp3)-H aminations and the synthesis of chiral 2-oxazolidinones.
Area of Science:
- Organometallic Chemistry
- Asymmetric Catalysis
- Chiral Ligand Design
Background:
- Development of chiral catalysts is crucial for asymmetric synthesis.
- Metal-centered chirality offers a unique strategy for catalyst design.
- Osmium complexes are versatile in catalysis but less explored for metal-centered chirality.
Purpose of the Study:
- To report the first chiral osmium catalyst with exclusive metal-centered chirality.
- To synthesize enantiomerically pure chiral-at-osmium complexes.
- To demonstrate the catalytic application in enantioselective C(sp3)-H aminations.
Main Methods:
- Synthesis of a non-C2-symmetric chiral-at-metal osmium complex featuring cyclometalated pyridylidene remote N-heterocyclic carbene ligands.
- Use of a chiral oxazoline ligand as an auxiliary to achieve enantiopurity (>99:1 e.r.).
- Application of the catalyst in ring-closing enantioselective C(sp3)-H aminations of azidoformates.
Main Results:
- Successful synthesis of a chiral osmium complex with chirality solely from the metal center.
- High enantioselectivity achieved using the chiral auxiliary ligand.
- Demonstration of catalytic enantioselective cyclization of azidoformates to chiral 2-oxazolidinones.
Conclusions:
- The reported osmium complex represents a significant advancement in metal-centered chirality.
- The catalyst is effective for enantioselective C(sp3)-H amination reactions.
- This work opens new avenues for designing chiral catalysts based on metal-centered chirality.
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