Enhancing the Equilibrium of Dynamic Thia-Michael Reactions through Heterocyclic Design
Alex E Crolais1, Neil D Dolinski2, Nicholas R Boynton2
1Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States.
Journal of the American Chemical Society
|June 23, 2023
Summary
Researchers developed new catalyst-free dynamic thia-Michael acceptors using an isoxazolone motif. These acceptors significantly enhance equilibrium constants, enabling robust dynamic covalent networks and linear polymers at room temperature.
Area of Science:
- Materials Science
- Polymer Chemistry
- Organic Chemistry
Background:
- The dynamic thia-Michael (tM) reaction is valuable in materials science and pharmaceuticals.
- Low equilibrium constants (Keq) have limited the full potential of catalyst-free tM reactions.
- Existing dynamic covalent materials often lack sufficient mechanical robustness.
Purpose of the Study:
- To develop novel catalyst-free, room-temperature dynamic thia-Michael acceptors with enhanced equilibrium constants.
- To create new dynamic covalent networks and linear polymers with improved properties.
- To investigate the relationship between acceptor structure, Keq, and material performance.
Main Methods:
- Synthesis of isoxazolone-motif bearing thia-Michael acceptors.
- Tuning electronic properties of acceptors to modulate Keq.
- Characterization of dynamic covalent networks and linear polymers.
- Mechanical testing of synthesized materials.
Main Results:
- Achieved a 2-orders-of-magnitude increase in Keq (∼1000 to ∼100,000 M⁻¹) compared to noncyclic analogues.
- Developed ditopic isoxazolone-based acceptors for network and polymer formation.
- Demonstrated tailorable thermomechanical properties and enhanced mechanical robustness.
- Enabled solution-state formation of linear polymers due to higher Keq.
Conclusions:
- Isoxazolone-based thia-Michael acceptors significantly improve reaction equilibrium.
- Enhanced Keq leads to more mechanically robust dynamic covalent materials.
- These new acceptors facilitate the development of advanced functional polymers and networks.
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