Studies On The Palladium And Ruthenium Catalyzed Carbon-heteroatom And Carbon-Carbon Bond Formation Reactions In Ionic Liquids

Room temperature ionic liquids, as a new green reaction medium as well as catalyst, possess super-ordinary physical chemistry properties and easily modified the structure of anions and cations. Ionic liquids were considered as the replacement of the commonly used volatile organic solvent. Recently, ionic liquids as a kind of green solvent and catalyst even as a carrier for catalyst have received much attention due to the important roles they played in organic reactions.Carbon-carbon and carbon-heteroatom bond-forming reactions are central to organic synthesis. Ionic liquids as a solvent, catalyst or carrier for catalyst in carbon-carbon and carbon-heteroatom bond-forming reactions have attracted great interest in organic synthesis. In this thesis, based on the reviewing developments of ionic liquids as a kind of green solvent, catalyst and carrier for catalyst in organic synthesis, we explored the possibility of transition-metal-catalyzed carbon-carbon and carbon-heteroatom bond-forming reactions in ionic liquids. The details are summarized as following:Part one: According to the literature procedure, we prepared a hydrophobic ionic liquid, namely, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm] PF6). We investigated the cross-coupling reaction of phenyl tributylstannyl selenide (PhSeSnBu3) with aryl and alkyl halides in the presence of Pd(PPh3)4 in [BMIm] PF6. It was found that the reaction proceeded smoothly at 80 oC to afford the corresponding diaryl and alkylaryl selenides in moderate to good yields, providing a green procedure for the formation of carbon-selenium. Ruthenium (III) chloride catalyzed acylation reactions of alcohols, phenols, and thiols in [BMIm] PF6 were also investigated. It was found that the acylation reactions could proceed smoothly at 45 oC to afford a variety of acetate in high yields, providing a green and practical method for acylation of alcohols, phenols, and thiols. In the two reactions above, the catalytic system composed of ionic liquid and the catalysts can be recycled many times without noticeable loss of the catalyst activity.Part two: According to the literature method, we prepared phenylstannane and alkynylstannanes and investigated Stille coupling reactions of organostannanes with aryl halides in [BMIm] PF6 in the presence of Pd(PPh3)4. It was found that the Stille reaction proceeded smoothly at 80 oC to give corresponding coupled products in good high yields. We also investigated the Sonogashira coupling reactions of aryl bromides with terminal alkynes in [BMIm] PF6. It was found that the Sonogashira coupling reaction proceeded smoothly at 60 ~ 80 oC in [BMIm] PF6, to afford a variety of aryl alkynes in high yields. In the two carbon-carbon bond-forming reactions, the [BMIm] PF6 and the catalysts could be recycled several times.