Electrochemical Synthesis of Polyfunctionalized Indoles in Aqueous Medium from Catechols and Ketene N,S-acetals

The electrochemical synthesis of o-benzoquinones and their in situ transformation is a versatile approach for the synthesis of polyhydroxylated aromatics. In the present paper, the electrochemical oxidation of catechol in the presence of ketene N,S-acetals as N,Cdoubly nucleophiles was first investigated using cyclic voltammetry technique. Then preparative scale of electrolysis was carried out to demonstrate that polyfunctionalized indoles could be one-pot synthesized under constant current electrolysis conditions. Finally, the reaction mechanism was proposed. Keywords: Anodic oxidation, catechols, ketene N, S-acetals, polyhydroxylated indoles.