Comparative Structural Analysis of Biarylphosphine Ligands in Arylpalladium Bromide and Malonate Complexes

The substitution of biarylphosphine ligands was shown to have a marked impact on the alpha/beta selectivity of the arylation of ester enolates. To get further insight into this effect, the solid-state structures of arylpalladium bromide and malonate complexes with four different biarylphosphine ligands were obtained by X-ray diffraction analysis. Structural differences were not very pronounced except for the conformationally restricted CPhos ligand, which showed a bidentate coordination mode in the oxidative addition complex, whereas the other ligands form dimeric species.