A transition-metal-free and reductant-free electrochemical strategy for the regioselective 1,4-hydrocarboxylation of 1,3-enynes with CO2 and H2O is reported. This method facilitates the synthesis of carboxyl-functionalized disubstituted 3,4-dienoic acids under mild conditions. Subsequent treatment with TMSCH2N2 allows for the construction of disubstituted 3,4-allenoate. Mechanistic studies, including cyclic voltammetry and control experiments, support the generation of CO2 radical anions via electroreduction, with the electronic properties of the aromatic rings playing a key role in this process.
Zhou et al. (Mon,) studied this question.