Walden inversionn.
/ˈvald(ə)n ɪnˌvəːʃn/, /ˈwɔːld(ə)n ɪnˌvəːʃn/, /ˈwɒld(ə)n ɪnˌvəːʃn/, U.S. /ˈvæld(ə)n ᵻnˌvərʒ(ə)n/, /ˈwɔld(ə)n ᵻnˌvərʒ(ə)n/, /ˈwɑld(ə)n ᵻnˌvərʒ(ə)n/ Chemistry.
A reversal of the configuration of substituents in a chiral molecule brought about in a substitution reaction; a reaction in which this occurs, esp. a bimolecular nucleophilic substitution causing a change of configuration from d to l or vice versa. Cf. inversion n. 8b.In a nucleophilic substitution the incoming group enters along the axis of the bond between the central atom and the leaving group, causing the other substituents to move to the opposite side of a plane perpendicular to this axis.
ΚΠ
1908 Proc. Chem. Soc. 24 91 (heading) A contribution to the chemistry of the Walden inversion.
1937 F. C. Whitmore Org. Chem. xxi. 480 In the Walden inversion, the process takes place on a single carbon atom instead of with a system of several atoms.
1968 J. March Adv. Org. Chem. x. 254 The Walden inversion has been found at a primary carbon atom..and at a sulfur (in sulfoxides), a silicon, and a phosphorus atom.
2004 Science 9 Jan. 190/1 Both steps involve Walden inversion of configuration at phosphorus.
This entry has been updated (OED Third Edition, June 2019; most recently modified version published online December 2021).
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n.1908