Domino synthesis of 2-arylbenzo[b]furans by copper(II)-catalyzed coupling of o-iodophenols and aryl acetylenes

A wide range of 2-arylbenzo[b]furans are synthesized through domino intermolecular C(aryl)-C(alkynyl) bond formation followed by intramolecular C(alkynyl)-O bond forming cyclization via copper(II)-catalyzed coupling of o-iodophenols and aryl terminal acetylenes. This method requires neither expensive palladium catalyst nor oxophilic phosphine ligands, can tolerate different functional groups. The methodology is successfully utilized in formal synthesis of β-amyloid aggregation inhibitor 5-chloro-3-[4-(3-diethylaminopropoxy)benzoyl]-2-(4-methoxyphenyl) benzofuran.