Nucleophilic aromatic substitution of hydrogen: a novel electrochemical approach to the cyanation of nitroarenes.

The nucleophilic aromatic substitution of hydrogen through electrochemical oxidation of the intermediate sigma complexes (Meisenheimer complexes) in simple nitroaromatic compounds is reported for the first time. The studies have been carried out with hydride and cyanide anions as the nucleophiles using cyclic voltammetry (CV) and preparative electrolysis. The cyclic voltammetry experiments allow for the detection and characterization of the sigma complexes and led us to a proposal for the mechanism of the oxidation step. Furthermore, the power of the CV technique in the analysis of the reaction mixture throughout the whole chemical and electrochemical process is described.