Mild and Efficient Tf2O-Mediated Synthesis of 3-Amino-1-benzofurans

Abstract

A mild and efficient procedure has been developed for the synthesis of 3-amino-1-benzofurans by intramolecular cyclization of the corresponding N,N-disubstituted phenoxyacetamides under the action of trifluoromethanesulfonic anhydride in the presence of 2-fluoropyridine in methylene chloride at room temperature. The proposed novel and efficient protocol has been successfully utilized to obtain a wide series of 3-amino-1-benzofurans with various substituents in the benzene ring and amino group.