Copper(II)Chloride-Mediated Cyclization Reaction of N-Alkoxy-ortho-alkynylbenzamides

A regioselective intramolecular cyclization/halogenation reaction of N-alkoxy-o-alkynylbenzamides with CuCl2/NCS was developed. The corresponding 3-(chloromethylene)isobenzofuran-1-ones were exclusively obtained via 5-exo-dig cyclization in moderate to excellent yields within 0.5-1 h. This approach has been successfully used to synthesize a biaryl compound by the Suzuki-Miyaura reaction.