Palladium complexes containing multidentate phenoxy-pyridyl-amidate ligands: Highly efficient catalyst for Heck coupling of deactivated aryl halides

N,N',N '',O-Tetrafunctional Pd(II) complexes prepared from the easily available amino acids are shown to be highly efficient catalysts for the Heck reaction of deactivated aryl bromides and iodides with high turnover numbers up to ca. 10(4) and moderate activity for the activation of aryl chlorides under phosphine-free conditions