Atom-Economic route to cyanoarenes and 2,2′-Dicyanobiarenes via Iron-Catalyzed chemoselective [2 + 2 + 2] cycloaddition reactions of diynes and tetraynes with alkynylnitriles

Abstract

An efficient protocol for the synthesis of cyanoarenes has been developed via an iron-catalyzed chemoselective [2 + 2 + 2] cycloaddition reaction of diynes with alkynylnitriles under mild reaction conditions with good to excellent yields. The reaction is catalyzed by the combination of FeCl2·4H2O as a metal source, 2-(2,6-diisopropylphenyl)iminomethylpyridine (dipimp) as a ligand, and Zn as a reducing agent in DME solvent. The protocol was further extended to the synthesis of 2,2′- dicyanobiarene skeletons from the reaction of tetraynes with alkynylnitriles.