Studies On The C-C Bond Forming Reactions Catalyzed By Palladium Or Copper Compounds

In this thesis, a series of phosphine or carbene adducts of cyclopalladated ferrocenylimines were prepared and their catalytic activities were evaluated in the Heck and Kumada reactions. The related reaction mechanisms were also studied. In addition, copper salt catalyzed three-component coupling reaction of aldehyde, amine, and alkyne (A3 coupling) was investigated.The application of N,N'-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) adduct of cyclopalladated ferrocenylimine complexⅡin the Heck reaction of aryl halides with olefins was studied (Scheme 1). It was found that the turnover number of 2.0×106 was obtained in reaction of iodobenzene with ethyl acrylate in the presence of 0.05 mmol% complexⅡwith K3PO4 as base, DMF as solvent. ComplexⅡalso could effectively catalyze the reaction of various aryl, heterocyclic bromides and activated aryl chlorides with olefins to give good to excellent yields. The mechanism of Heck reaction promoted by palladacycles was also studied. On the basis of kinetic studies, in situ 13C NMR spectra investigations and Hg poisoning experiments, it was proposed that the Heck reaction catalyzed by carbene adduct of cyclopalladated ferrocenylimine proceeded through a classical Pd(0)/Pd(Ⅱ) cycle and such palladacycle was only a reservoir of the catalytically active Pd(0) species. Cyclopalladated ferrocenylimine complexesⅠ-Ⅳwere applied in the Kumada coupling reaction of aryl halides with aryl Grignard reagents (Scheme 2). In comparison with tricyclohexylphosphine (PCy3) adduct of cyclopalladated ferrocenylimine complexⅥ, complexⅡwith strongly electron-donating and sterically hindered carbene was found to be the higher catalytic activity.We investigated the influence of solvent, additive, reaction temperature and substrate on the Kumada reaction. It was found that complexⅡexhibited highly catalytic activity for the coupling of aryl bromides with Grignard reagents in the case of 2 equiv. LiCl as additive, THF as solvent and substrates with various functional groups (such as CN, Boc and vinyl etc.) at room temperature. Notably, some important intermediates of drugs were obtained. This reaction system was also very efficient for the coupling of aryl chlorides with Grignard reagents, especially with sterically hindered Grignard reagents. A wide range of bi-and tri-ortho-substituted biaryls were efficiently obtained in good to excellent yields in the presence of 0.5 mol % catalyst at 60℃(Scheme 3). Three-component coupling reaction of aldehyde, amine, and alkyne in a one-pot procedure catalyzed by CuI was studied (Scheme 4). It was found that with easily available succinic acid as additive, the three-component coupling reaction was efficiently promoted in the presence of 3 mol% CuI. The functional groups such as fluoro, chloro, bromo, methoxy, hydroxy and vinyl could be compatible with this coupling. Using this method, various propargylamines were generated in good to excellent yields.