Bromine-mediated cyclization of 1,4-diaryl buta-1,3-diyne to 1,2,3-tribromo-4-aryl naphthalene

Bromine-mediated intramolecular cyclization of 1,4-diaryl buta-1,3-diynes has been developed for the construction of naphthalene motifs. A number of 1,2,3-tribromo-4-aryl naphthalenes are synthesized under mild reaction condition by the 6-endo-dig electrophilic cyclization of the corresponding 1,4-diaryl buta-1,3-diynes by Br2 in moderate to excellent yields. This methodology has been successfully extended to the synthesis of 1,2,3,4-tetraphenyl naphthalene derivatives.