Structure and catalytic activity of organopalladium(II) complexes based on 4,5-dihydro-1H-imidazol-5-one derivatives

The paper describes preparation of a chiral bidentate ligand – 2-(2-bromophenyl)-4,5-dihydro-1H-imidazol-5-one, and a tridentate ligand – 2-bromo-1,3-bis(4,5-dihydro-1H-imidazol-5-on-2-yl)benzene, whose oxidative addition reaction with Pd(0) giving neutral organopalladium(II) complexes has been studied. The structure of these complexes was studied by means of NMR spectroscopy and X-ray diffraction. After transformation of the neutral organopalladium(II) complexes into the corresponding ionic species the latter were studied as enantioselctive catalysts for asymmetric Friedel–Crafts alkylation and Michael addition.

New chiral Pd–pincer complexes derived from substituted 4,5-dihydro-1H-imidazol-5-one ligands have been prepared and their structure has been determined by means of NMR spectroscopy and X-ray diffraction. The cationic organopalladium(II) complexes have been studied as enantioselctive catalysts for asymmetric Friedel–Crafts alkylation and Michael addition.Figure optionsDownload as PowerPoint slideResearch highlights
► New 4,5-dihydro-1H-imidazol-5-one NC and NCN pincer ligands have been prepared.
► NC and NCN Pincer ligands 3 and 7 could be easily palladated by Pd(0).
► There was found a significant deviation from square-planar arrangement in complex 8.
► The Pd-complexes catalyse the Friedel–Crafts alkylation and the Michael addition