Heating 1, 2-bis (phenylethynyl) benzene in the presence of 1, 4-cyclohexadiene at temperatures ranging from 260 to 360° C yielded the expected Bergman product, 2, 3- diphenylnaphthalene, as only a minor product (< 3%) under all reaction conditions studied. The major products, resulting from one or more phenyl shifts, were 1, 3-and 1, 4- diphenylnaphthalene which formed in up to 16% and 11% yield, respectively. Although ...
