Synthesis of a novel class of benzofurans via a three-component, regiospecific intramolecular heterocylization reaction

A new, convenient, and environmentally benign three-component synthesis of a novel class of benzofurans is developed by condensing different arylglyoxals, benzamide, and phenolic substrates under solvent-free conditions. These reactions are catalyzed by tungstate sulfuric acid (TSA) as a safe, clean, and recyclable solid acid. The method is operationally simple and provides access to a variety of 2-aryl-3-benzamido benzofurans in good to excellent yields.