Fine-Tuning Substrate-Catalyst Halogen-Halogen Interactions for Boosting Enantioselectivity in Halogen-Bonding
Alica C Keuper1, Kevin Fengler1, Florian Ostler1
1Organic Chemistry Institute, University of Münster, Correnstraße 36/40, 48149, Münster, Germany.
Angewandte Chemie (International Ed. in English)
|May 25, 2023
Summary
Researchers developed a novel halogen-bonding catalysis method for high enantioselectivity. This strategy uses tailored halogen-halogen interactions to control chirality transfer in asymmetric catalysis.
Area of Science:
- Organic Chemistry
- Catalysis
- Supramolecular Chemistry
Background:
- Asymmetric catalysis often faces limitations due to the nature of halogen bonds (XB).
- Developing enantioselective halogen-bonding catalysis requires overcoming these intrinsic challenges.
Purpose of the Study:
- To develop a new approach for highly enantioselective halogen-bonding catalysis.
- To design fine-tuned halogen-halogen interactions for enhanced enantiocontrol.
Main Methods:
- Exploiting both Lewis base and sigma-hole sites of halogen substituents on substrates.
- Utilizing tetrakis-iodotriazole multidentate anion-binding catalysts.
- Forming a tight catalyst-substrate-counteranion chiral complex.
Main Results:
- Achieved remarkable enantioselectivities up to 95:5 er (90% ee) in a model reaction.
- Demonstrated high levels of chirality transfer through controlled induction.
- Successfully applied the strategy to dearomatization of halogen-substituted (iso)quinolines.
Conclusions:
- The developed strategy effectively overcomes limitations in asymmetric catalysis using halogen-bonding.
- This approach enables precise control over chirality transfer via tailored substrate-catalyst interactions.
- The method offers a promising pathway for advanced enantioselective synthesis.
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