Computational Evidence for the Existence of CuIII Intermediates in Addition and Substitution Reactions with Dialkylcuprates

When the copper center is stabilized by donor ligands such as H2O and NH3, trialkylcopper compounds correspond to energy minima at all levels of theory used in the calculations (MP2, SCRF, BLYP). These results support proposals that such species are intermediates in cuprate addition and substitution reactions and at the same time suggest that descriptions of trialkylcopper systems as CuII rather than CuIII complexes may be more appropriate.