Studies on the the Unsymmetric NCN-palladium Pincer Complex Synthesis and Catalytic in Sonogashira Coupling Reaction
|Keywords||Asymmetric NCN Clamp compound Aldimine Sonogashira reaction|
The synthesis of this thesis, two types of novel asymmetric 3 - (2 - oxygen pyridine ) benzaldehyde ligands and their corresponding NCN pincer palladium compounds , characterized by its structure , and effects of the pincer palladium compounds synthesized in under mild conditions catalyzed Sonogashira coupling reaction . The main work is as follows : a 3 - (2 - oxygen - pyridyl) benzene the formaldehyde ligand and the corresponding asymmetric NCN pincer palladium compound synthesis and characteristics of raw materials, cheap and easy to get inter- hydroxybenzaldehyde and 2 - bromopyridine after off hydrogen bromide to give compound 3 - (2 - oxo - pyridyl) benzaldehyde, and the compound in CH2C12 in a series of aromatic amines and aliphatic amines at room temperature was stirred for four corresponding imine compound 1a -1d , and further with the palladium chloride the synthetic reaction of the corresponding metal palladium compound 2a-2d (Scheme 1) compound la-1d without separation , is added directly to the reaction mixture an excess of NaBH4 reduction , to give a new class of ligands 3a-3d , and 3a -3d , and PdCl2 reaction the corresponding metal compound 4a-4d (Scheme 2). 2a -2d , 3a-3d , 4a -4d are new compounds by means of IR, 1H NMR, 13C NMR and MS, the structure of the compound was characterized , which 2c , 4b , 4d further by the X-ray single crystal diffraction structure confirmation . . Asymmetric NCN pincer palladium compounds in the Sonogashira coupling reaction studied asymmetrical NCN pincer palladium catalyzed aromatic halides phenylacetylene Sonogashira coupling reaction ( Scheme 3) , no copper do to help catalysts are : the amount of the catalyst , solvent , base, reaction temperature and time , screening and optimization . Best reaction conditions as follows: no inert gas protection , 2 mol% catalyst 2b , pure water as a solvent , an alkali K3P04 70 ° C for 12 hours . Under this condition , a good catalytic results obtained on a series of halogenated aryl group and the coupling reaction of phenylacetylene , and the yield up to 99% .