Nickel-Catalyzed Activation And Transformation Of C-Cl,C-F,C-O And C-N Bonds

Chapter1deals with synthesis and characterization of new nickel complexes and catalysis of the complexes in the Kumada coupling of aryl chlorides and aryl flurides. A series of nickel complexes bearing novel phosphine ligands were synthesized and characterized. Two of the complexes,(Cy2PR)NiCl2and (i-Pr2PR)NiCl2, efficiently catalyze cross-coupling of aryl chlorides and fluorides with aryl Grignard reagents. In the presence of LiCl, ZnCl2and H2O, the efficient coupling of functionalized aryl chlorides with aryl Grignard reagents using (Cy2PR)NiCl2or (i-Pr2PR)NiCl2as the catalyst can be performed.Chapter2is about activation and transformation of sp2C-O bonds. The research on the cross-coupling of aryl/alkenyl methyl ethers with aryl Grignard reagents catalyzed by nickel complexes was presented. Nickel complexes (Cy2PR)NiCl2and (i-Pr2PR)NiCl2could efficiently drive the substitution of MeO-in aryl/alkenyl methyl ethers with aryl Grignard reagents as the nucleophiles. This method shows a broad substrate scope and leads to good to excellent yields of the aryl-aryl or alkenyl-aryl cross-coupling products.Chapter3describes catalytic activation and transformation of aryl C-N bonds. The Ni-catalyzed cross-coupling of aryltrimethylammonium salts with aryl/alkyl zinc reagents was carried out. Monodentate and bidentate phosphine coordinated Ni(II) complexes can drive the reaction to proceed smoothly in a1:1mixture of THF and NMP. Ni(PCy3)2Cl2leads to the best results. Use of arylzinc reagents can ensure a wide range of functional group compatibility. In addition, this study shows that the aryltrimethylammonium iodides with electron withdrawing group on the aromatic ring can efficiently couple with methyl or benzyl zinc reagents under the same conditions. Alkyl zinc reagents containing β-hydrogen will lead to the hydrogenation of aryltrimethylammonium iodides to a certain extent.Chapter4introduces cross-coupling of aryltrimethylammonium iodides and aryl-or methylmanganese reagents catalyzed by amido pincer nickel complexes. In this approach, arylmanganese reagents were found to react with aryltrimethylammonium iodides in THF/NMP within30min. catalyzed by complex5b. For the activated substrates the coupling can proceed at room temperature, and for the deactivated substrates the reaction was carried out at elevated temperature. Functional groups such as F, nitrile, ester and carbonyl can be tolerated.