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Updated: Aug 11, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
The Walden cycle revisited: a computational study of competitive ring closure to alpha- and beta-lactones
J Grant Buchanan1, Richard A Diggle, Giuseppe D Ruggiero
1Department of Chemistry, University of Bath, UK.
Abstract:
The text-book Walden cycle which interconverts the stereochemical configurations of chlorosuccinic and malic acids involves a beta-lactone intermediate in preference to an alpha-lactone intermediate because the O(nuc) C Cl angle in the transition structure for the former (174 degrees) is more favourable than that for the latter (139 degrees), as determined by PCM(epsilon = 78.4)/B3LYP/6-31+G* calculations; the smaller ring-strain energy of the beta-lactone contributes little to the reactivity difference.
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