Enantioselective hydrogen atom relay via non-covalent catalyst assembly
Navadheer Yalamanchili1, Jules Hugo Alexandre1, Robert L Anderson1
1Laboratory of Asymmetric Catalysis and Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
This study introduces a novel method for creating chiral catalysts in situ using self-assembling chiral phosphoric acids and thiols. This approach enables enantioselective hydrogen atom transfer reactions, crucial for synthesizing chiral molecules.
Area of Science:
- Organic Chemistry
- Catalysis
- Asymmetric Synthesis
Background:
- Chiral molecules are vital for biological functions, often containing tertiary stereocenters.
- Hydrogen Atom Transfer (HAT) is key for creating stereocenters but achieving enantioselectivity with chiral catalysts is challenging.
- Existing methods for designing chiral HAT catalysts struggle with short-lived intermediates.
Purpose of the Study:
- To develop a novel platform for generating chiral HAT catalysts in situ.
- To overcome limitations in enantiocontrol for asymmetric HAT reactions.
- To enable new asymmetric radical transformations.
Main Methods:
- In situ catalyst generation via non-covalent self-assembly of chiral phosphoric acids and 2-mercaptopyridines.
- Utilizing phosphoric acid as a modular chiral element to activate achiral thiols.
- Photochemical deracemization of 2-aryl pyrrolidines using the self-assembled catalysts.
Main Results:
- A new combinatorial space of chiral HAT catalysts was accessed.
- Successful photochemical deracemization of 2-aryl pyrrolidines was achieved.
- Demonstrated enantioselective hydrogen atom relay orchestrated by a single chiral assembly.
Conclusions:
- Non-covalent self-assembly provides a powerful strategy for creating chiral HAT catalysts.
- This approach enables efficient deracemization and asymmetric synthesis.
- The platform opens new avenues for discovering asymmetric radical transformations.
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