CO 2 Transient Promotion Function Enabled the Selective Electrochemical Transformation of Imines.

An unprecedented transient promotion function (TPF) of CO 2 in the electrochemical hydrogenation/deuteration of imines (especially α-iminonitriles) is reported. The TPF influence of CO 2 results from the introduction of CO 2 that disperses the negative charges of the imine radical anion intermediate. The resulting redistribution of electrons leads to a lower reduction potential of the CO 2 -substituted imine radical anion and thus facilitates the succeeding one-electron reduction. CO 2 is finally released via spontaneous decarboxylation to complete the transient promotion process.