N-Heterocyclic Carbenes (NHCs) Containing N-C-Palladacycle Complexes: Synthesis and Reactivity in Aryl Amination Reactions

Starting from the corresponding dimer, new saturated NHC-containing N,N-dimethyl biphenylamine (DMBPA) palladacycle complexes have been synthesized and fully characterized. Catalytic activity of these well-defined, air- and moisture-stable palladium(II) complexes was evaluated in the Buchwald-Hartwig amination involving a range of unactivated aryl chlorides. From a practical perspective, the reaction conditions required when using [(NHC)Pd(palladacycle)Cl] systems are very appealing. The organic biphenyl ligand used in the synthesis of the pallaclacycles has been synthesized using a Suzuki-Miyaura cross-coupling employing the novel palladacycle-NHC complexes.