Regioselectivity of Electrochemical C-H Functionalization Via Iminium Ion

The electrochemical C-H functionalization of carbamates via N-acyliminium ion is a very useful way for synthesizing biologically active and pharmaceutical products but its mechanism is not fully understood yet, specially referring to the anomalous regioselectivity that leads to the functionalization in the less substituted site which would allow to modulate the regioselectivity of the process in the asymmetric carbamates. Cyclic voltammetry experiments (with both static and rotating disk electrode) of the α-alkoxylation of carbamates prove that the mechanism for this reaction is of the type ECEC with the first two steps occurring in a concerted manner, a conclusion that is also corroborated by theoretical (DFT) values of absolute redox potentials. Further theoretical calculations show that the cause of the anomalous regioselectivity lies in the combination of the dipole moment vector of the asymmetric carbamates with the concerted ECEC mechanism.