title: The Walden cycle revisited: a computational study of competitive ring closure to alpha- and beta-lactones.
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.
authors.affiliation: Department of Chemistry, University of Bath, UK.
authors.forename: J Grant
authors.initials: JG
authors.lastname: Buchanan
authors.forename: Richard A
authors.initials: RA
authors.lastname: Diggle
authors.forename: Giuseppe D
authors.initials: GD
authors.lastname: Ruggiero
authors.forename: Ian H
authors.initials: IH
authors.lastname: Williams