Syntheses Of Ferrocenyl Phosphine And N-Heterocyclic Carbene Ligands And Their Applications To The Pd-Catalyzed Suzuki Cross-Coupling Reaction

Suzuki cross-coupling is one of important methods to form biphenyl derivatives. It has become an important tool for the modern organic synthesis and has been extensively utilized in the preparation of organic optoelectronics, medicines, fine chemicals, etc.In chapter 2, six asymmetry 1-(1-ferrocenylethyl)-3-substituted-1-imidazolium iodides 7 (7a, 7b, 7c, 7d, 7e and 7f) were synthesized. The effect of bases on Pd-catalyzed Suzuki cross-coupling reaction was investigated. The results illustrated that the combination of Cs₂CO₃/1, 4-dioxane was a good system. The steric ligand 7d displayed the best catalytic activity in this system. In the presence of 1 molï¼…Pd, Pd(OAc)₂/7d (mole: mole=1: 1.3), 90-97ï¼…yields were isolated.In chapter 3, four new phosphine ligands have been synthesized, including two ether oxygen-phosphinoferrocenyl ligands 11(11a and 11b) and two immobilized phosphinoferrocenyl ligands 12(12a and 12b) based on Merrifield synthesized from(11a and 11b). These four ligands(11a, 11b, 12a or 12b) demonstrated efficient activity for Pd-catalyzed the coupling of aryl bromides with aryl boronic acid in CH₃COOK/1, 4-dioxane. In the presence of 0.1 molï¼…Pd, Pd(OAc)₂/11(Pd: 11=1: 1.3), the yields were 93-95ï¼…for coupling of 4-bromotoluene with phenylboronic acid. The system of Pd(OAc)₂/12a could be recycled 2 times, and the catalyst was easily separated from products.In chapter 4, three new 1-[1-(2-diphenylphosphinoferrocenyl)ethyl]-3-substituted-1-imidazoles iodides containing PEG 15(15a, 15b and 15c) were synthesized. In 1, 4-dioxane, P-NHC ligands 15 containing PEG displayed high catalytic behavior in the cross-coupling reactions of aryl bromides with arylboronic acid, in comparation to the P-NHC ligands 1-[1-(2-diphenylphosphinoferrocenyl)ethyl]-3-methyl-1-imidazoles iodide. In the presence of K₂CO₃, 1, 4-dioxane, 0.1 molï¼…Pd, Pd(OAc)₂/15 (Pd: 15=1: 1.1), 85-95ï¼…yields were obtained.The influence of ligands, additives, and bases was studied in the Pd-catalyzed Suzuki cross-coupling reaction in water. The results showed the additive of PEG played a great role on coupling reactions using 15. In the presence of K₂CO₃, Water/PEG-400(W: W-1:1), 0.1 molï¼…Pd, Pd(OAc)₂/15(Pd: 15-1: 1.1), coupling of aryl bromides with arylboronic acid afforded 93-95ï¼…yields. Higher yields were isolated after prolonged heating, when the loading of Pd was decreased to 0.01-0.001 molï¼…Pd, Pd(OAc)₂/15c(bromobenzene, TON=95000).