A Facile Synthesis of α‐Aryl α‐Oxoheterocyclic Ketene N,N‐Acetals Bearing an Electron‐Rich Catechol Subunit–An Electrochemical Oxidative Approach

Abstract

Abstract Heterocyclic ketene N,N‐acetals are versatile building blocks for the synthesis of nitrogen‐containing heterocyclic compounds. In the present work, the anodic oxidation of catechols 2a – f in the presence of α‐oxoheterocyclic ketene N,N‐acetals 1a – d has been investigated using cyclic voltammetry and controlled‐potential electrolysis methods. These results indicate that α‐oxoheterocyclic ketene N,N‐acetals could undergo Michael addition to the anodically generated o ‐benzoquinones and produce α‐carbon‐arylated products in good yields. This approach provides effective and “green“ access to the synthesis of α‐aryl α‐oxoheterocyclic ketene N,N‐acetals containing an electron‐rich aromatic ring. In addition, density functional theory calculations were performed to explain the exclusive formation of α‐carbon‐arylated products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)