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Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
Published on: January 17, 2020
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A complementary pair of enantioselective switchable organocatalysts
Guillaume De Bo1, David A Leigh1, Charlie T McTernan1
1School of Chemistry , University of Manchester , Oxford Road , Manchester , M13 9PL , UK .
Chemical Science
|November 18, 2017
Summary
Researchers developed switchable bifunctional catalysts for conjugate addition reactions, achieving high enantioselectivity (up to 95% e.r.). These catalysts offer controllable ON/OFF states, crucial for optimizing chemical synthesis.
Area of Science:
- Organic Chemistry
- Catalysis
- Asymmetric Synthesis
Background:
- Developing controllable catalysts is essential for efficient and selective chemical transformations.
- Switchable catalysts offer dynamic control over reaction pathways and outcomes.
- Bifunctional catalysts can perform multiple roles, enhancing reaction efficiency.
Purpose of the Study:
- To design and synthesize enantioselective switchable bifunctional catalysts.
- To investigate the ON/OFF switching capabilities and their impact on conjugate addition reactions.
- To explore the potential for simultaneous operation of complementary catalysts for stereochemical control.
Main Methods:
- Synthesis of a pair of enantioselective switchable bifunctional organocatalysts.
- Evaluation of catalyst performance in various conjugate addition reactions.
- Characterization of catalyst switching behavior (ON/OFF states) and reaction rate ratios.
- Testing of simultaneous catalyst operation for stereochemical switching.
Main Results:
- The catalysts promoted conjugate addition reactions with high enantioselectivity (up to 95% e.r.) and conversion (up to 95%).
- Achieved high catalyst ON:OFF ratios (up to 98:2 and 1:99) with significant rate differences (up to 16:1) between states.
- Demonstrated stable ON-OFF-ON and OFF-ON-OFF switching cycles.
- Simultaneous operation of the catalyst pair in one vessel was unsuccessful due to mutual inhibition.
Conclusions:
- The developed catalysts represent a first-generation complementary pair of enantioselective switchable organocatalysts.
- The ON and OFF states exhibit distinct catalytic activities and can be reversibly controlled.
- Mutual inhibition between the catalysts prevents simultaneous operation, highlighting a challenge for future catalyst design.
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