Mechanism of oxidative carbonylation of phenylacetylene and methylacetylene. Generation and experimental discrimination of hypotheses

Formal and informal methods for advancing hypotheses on mechanisms were use d in a study of the oxidative carbonylation of phenylacetylene to methyl ph enylpropiolate catalyzed by the PdCl2-CuCl-CuCl2 system. The hypotheses rem aining after discrimination and consistent with all experimental data inclu de the steps of formation of the Cu-I alkynyl complex, transfer of the phen ylethynyl group from Cu-I to Pd-II, insertion of carbon monoxide into a Pd- C or Pd-OMe bond of the Pd-II sigma-alkynyl complex. Comparison of the form al and informal methods for advancing hypotheses confirmed a higher efficie ncy of the first method.