Summary: A first route to the isomerisation of erythro‐ and threo‐2,3‐disubstituted succinyl units in alternating alkene‐maleic acid copolymers is presented. The isomerisation reactions of the disodium salt of ethene‐maleic acid copolymer were carried out in aqueous solution at 180–240 °C in an autoclave. It is demonstrated that the erythro‐content can be changed from 17% up to 67%. The dissociation of methine C H bonds with the intermediate formation of a sp2 hybridised carbon is proposed as the mechanism.
Isomerisation equilibrium between the threo‐ and erythro‐form of the 2,3‐disubstituted succinyl unit.
