Lewis acid-promoted cyclizations of o-alkyloxyphenyl-substituted ynamides are described for the general construction of medicinally relevant 2-amidobenzofurans. A diverse array of 3-acyl-2-amidobenzofurans could be effectively constructed via a SnCl4-promoted intermolecular reaction. And the 3-unsubstituted 2-amidobenzofurans could be obtained efficiently through a ZnCl2-promoted intramolecular reaction.
