Electrochemical synthesis of isothiocyanogen and its reactivity in thiocyanation reactions

Abstract

The electrochemical oxidation of (iso)thiocyanic acid was studied for the first time by complex of experimental (cyclic voltammetry, controlled potential electrolysis) and theoretical (digital simulations, quantum chemical calculations) methods.We unexpectedly discovered that electrooxidation of (iso)thiocyanic acid leads to isothiocyanogen (and not to thiocyanogen, as in the oxidation of thiocyanate salts). It is the first case where isothiocyanogen was synthesized in solution under mild conditions. The reactivity of isothiocyanogen has been evaluated using indole thiocyanation as a model reaction. The high yield of 3-thiocyanato-1H-indole (93%) obtained in this process underscores its practical interest.