The Synthesis Of Chiral Imidazoline PCN Pincer Pd Complexes And Their Catalytic Properties

This thesis discusses the synthesis and characterization of chiral phosphinite (and aminophosphine)-imidazoline PCN pincer palladium complexes, and their applications in asymmetric addition of diarylphosphines to enones.1.Synthesis and characterizaiton of chiral phosphinite-imidazoline PCN pincer palladium complexesImidazolinyl m-phenol compounds2a-d were prepared from cheap and commercially available m-hydroxybenzoic acid by four steps. With the expected ligand precursors in hand, the one-pot phosphorylation/palladation reaction was attempted in order to get the chiral pincer Pd(II) complexes3a-e (Scheme1). All of the new compounds2a-d and3a-e were characterized by elemental analysis (HRMS for2a-d),1H NMR,13C NMR,31P NMR and IR spectra. The molecular structure of complex3a was confirmed by X-ray single crystal diffraction.2. Synthesis and characterizaiton of chiral (nitrogen) phosphite-imidazoline PCN pincer palladium complexesImidazolinyl m-phenylamine derivatives6a-c were prepared by four steps from low-cost and commercially available m-Nitrobenzoic acid. With the expected ligand precursors in hand, the one-pot phosphorylation/palladation reaction was attempted in order to get the chiral pincer Pd(II) complexes7a-c(Scheme2).All of the new compounds5b-c,6b-c,7a-c were characterized by elemental analysis (HRMS for5b-c,6b-c),1H NMR,13C NMR,31P NMR and IR spectra.3.Applications of PCN pincer complexes in asymmetric addition reaction.The enantioselectivities and activities of the pincer Pd(II) complexes (3a-e,7a-c) in asymmetric addition reaction of diarylphosphine to electron-deficient olefins (Scheme3) were investigated.It was found that complex3a gave better results, affording the products in>99%yield and98%ee.