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Chiral cyclometalated iridium complexes for asymmetric reduction reactions
Jennifer Smith1, Aysecik Kacmaz, Chao Wang
1Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK. jxiao@liv.ac.uk.
Chiral iridium complexes were synthesized and tested for asymmetric transfer hydrogenation. The most effective complexes achieved up to 77% enantioselectivity in reducing pyridinium ions and 63% ee in ketone amination.
Area of Science:
- Organometallic Chemistry
- Asymmetric Catalysis
Background:
- Chiral ligands are crucial for enantioselective synthesis.
- Cyclometalated iridium complexes offer unique catalytic properties.
Purpose of the Study:
- To synthesize novel chiral cyclometalated iridium complexes.
- To evaluate their efficacy in asymmetric transfer hydrogenation reactions.
Main Methods:
- Synthesis of iridium complexes using chiral 2-aryl-oxazoline and imidazoline ligands.
- Cyclometalation with [Cp*IrCl2]2.
- Asymmetric transfer hydrogenation using formic acid as the hydrogen source.
Main Results:
- Successful synthesis of a series of chiral cyclometalated iridium complexes.
- Demonstrated varying catalytic activity and enantioselectivity.
- Achieved up to 63% enantiomeric excess (ee) in asymmetric reductive amination of ketones.
- Achieved up to 77% ee in the reduction of pyridinium ions.
Conclusions:
- Chiral cyclometalated iridium complexes are effective catalysts for asymmetric transfer hydrogenation.
- Ligand structure influences catalytic performance and enantioselectivity.
- These complexes show promise for enantioselective synthesis of valuable compounds.
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