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Computational Studies of Chiral Epoxide Radicals
Kathleen M Morgan1, Lauren A Brown1, Camryn C Cole1
1Department of Chemistry, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, Louisiana 70125, United States.
The Journal of Organic Chemistry
|July 16, 2025
Summary
This study compares the reactivity of simple epoxides and their radicals using advanced computational methods. Substituents significantly influence radical inversion barriers and ring-opening reactions, with perfluorination increasing reaction barriers.
Area of Science:
- Organic Chemistry
- Computational Chemistry
- Chemical Reactivity
Background:
- Epoxides are strained cyclic ethers widely used as commodity chemicals and synthetic intermediates.
- Understanding epoxide reactivity is crucial for developing new synthetic methodologies.
Purpose of the Study:
- To computationally investigate and compare the gas-phase reactivity of simple epoxides and their corresponding carbon-centered radicals.
- To analyze the influence of various substituents on epoxide radical properties and reaction pathways.
Main Methods:
- High-level ab initio calculations using G4 and W1BD composite methods.
- Inclusion of solvent effects via the polarized continuum model (PCM).
Main Results:
- Calculated C-H bond dissociation energies for epoxide radical formation.
- Quantified substituent effects on the nonplanar geometry of epoxide radicals and their inversion barriers.
- Investigated competitive ring-opening reactions of epoxide radicals to form vinoxy radicals.
- Observed elevated reaction barriers for polyfluorinated epoxide radicals.
Conclusions:
- Substituents profoundly impact epoxide radical inversion barriers and ring-opening reaction dynamics.
- Perfluorination significantly stabilizes epoxide radicals against inversion and ring-opening.
- Computational findings provide insights into the fundamental reactivity of epoxides and their radical intermediates.
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