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 α/β 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.