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Updated: Mar 13, 2026

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
Published on: December 16, 2022
Revisiting the mechanistic origins of Thiele's ester dimerization: probing the reliability of predictive models for
1Department of Chemistry, University of Victoria, Victoria, BC, CanadaV8W 3V6. wulff@uvic.ca.
Abstract:
The Diels-Alder dimerization of cyclopentadiene carboxylic acid (or ester) affords only three products out of a total of 36 possible regioisomers. In this Communication, we compare two competing conceptual models for their ability to rationalize the selective formation of these three compounds. We find that calculated ΔHf values and orbital energy levels are sufficient to describe gross reactivity for the system, but that orbital coefficient arguments (and frontier molecular orbital theory in general) do not reliably predict the regioisomeric outcome for the reaction. By contrast, Deslongchamps' radical stabilization logic (a consequence of the bent bond model of reactivity) correctly predicts all three Diels-Alder products. We anticipate that these data will stimulate broader consideration of radical stabilization effects as a predictive tool for cycloaddition chemistry.
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Stability of Substituted Cyclohexanes
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...