Mechanism of anodic cyanation

Abstract

The mechanism of the anodic cyanation of aromatic compounds has been investigated, using the determination of isomer distributions as an experimental tool. The reaction has the general characteristics of a homogeneous electrophilic substitution process, being highly selective with regard to attack at the ring positions in monosubstituted aromatic substrates. Nuclear substitution is highly favoured over side-chain substitution in alkylaromatic compounds, such as toluene and mesitylene. For comparison, a study of a homolytic cyanation reaction has been performed. The data obtained, as well as the comparison with the anodic acetoxylation reaction, are in agreement with a mechanism involving a cyanide ion assisted two-electron transfer from the aromatic compound to the anode as the product-forming step.