Free-radical addition of esters to esters of citraconic, itaconic, and acetylenedicarboxylic acids

Abstract

1. A new C-C bond on homolytic addition of dimethyl esters of succinic, glutaric, and adipic acids to the dimethyl or diethyl ester of citraconic, itaconic, and acetylenedicarboxylic acids is formed between theα-C atom of the acyl part of the ester of the alkanedicarboxylic acid and the least substituted C atom of the C=C bond of the ester of the unsaturated acid. 2. As an acceptor of radicals generated from esters of alkanedicarboxylic acids, the ester of citraconic acid is substantially less effective than the esters of maleic, itaconic, and acetylenedicarboxylic acids. The latter are close to one another in capability of forming addition products with esters of succinic, glutaric, and adipic acids. 3. The principal products of homolytic reaction of dimethyl esters of glutaric and adipic acids with the dimethyl ester of acetylenedicarboxylic acid are respectively the tetramethyl esters of 2-pentene-1,2,3,5-tetracarboxylic acid and 2-hexene-1,2,3,6-tetracarboxylic acid.