The Synthesis Of Pincer Nickel Complexes And Their Applications In Michael Addition And Suzuki-Miyaura Cross-Coupling Reaction

In this thesis, five neutral chiral pincer NCN-Ni complexes 3a-e, two neutral pincer PCN-Ni complexes 9b-10b, and two neutral, asymmetric pincer PCP-Ni complexes llb-12b were synthesized by direct metalation via the C-H activation of the related ligands.Two cationic complexes 4a and 4c were obtained from the reaction of 3a and 3c with AgBF4. On one hand we studied the catalytic activities of cationic complexes 4a and 4c in the Michael addition of ethyl 2-cyanopropanoate to methyl vinyl ketone, on the other hand the catalytic activities of complexes 3a,4c, and 9b-12b in the Suzuki-Miyaura cross-coupling reaction of Aryl Tosylates with aryl boronic acids were studied too.Three known bis(amido) alcohols la-c and three Phebim-H ligands 2a-c were prepared using the published procedure. Complexes 1d and 2e-f were synthesized using an analogous procedure. The neutral Ni(Phebim)Cl complexes 3a-e could be conveniently prepared by direct C-H activation of the related Phebim-H ligands 2a-e and anhydrous NiCl2 in good yield. Reacting 3a and 3c with AgBF4 could give cationic complexes 4a and 4c, respectively. Complexes Id,2e-f,3a-e,4a and 4c were well characterized by IR spectra, NMR, elemental analysis(or HRMS) et al. The molecular structures of 3a-c and 4c were determined by X-ray single crystal analysis. Complexes 8 and 10a were synthesized using the published or analogous procedure. m-hydroxylbenzoicalcohol was obtained from the reduction of m-hydroxylbenzaldehyde by NaBH4, followed by one-pot phosphorylation/metalation reaction with diphenylchlorophosphine and anhydrous NiCl2, resulting in the aymmetric pincer complexes 9b-12b.These complexes were well characterized by IR spectra, NMR, elemental analysis, X-ray single crystal et al. The catalytic activities of cationic complexes 4a and 4c in the Michael addition((A) in Scheme 4) of ethyl 2-cyanopropanoate to methyl vinyl ketone were investigated. Complexes 4a and 4c were found to be effective catalysts with a catalyst loading of 5 mol%, producing the adduct in>99% yield with no ee. Complexes 3a,4c and 9b-12b were used to catalyze the Suzuki-Miyaura cross-coupling reaction((B) in Scheme 4), and we discussed the influence of the heteroatoms in the side arms of catalysts, additional P ligands, solvents, and different bases on these reactivities. Then, a series of Aryl Tosylates were tested under the optimized conditions.