Studies On The Suzuki Coupling Reactions And Condensation Reactions In Green Media.

Recently, the research of using water as organic reaction media is one hot point of the research of alternative reaction media in the Green and Sustainable Chemistry. The use of water as the reaction media has several benefits, including low cost, improved safety, abundance and the easier phase separation and so on, bring about good effects on separation, chemical synthesis, etc.. However, the majority of organic compounds are insoluble in water, the application of water in chemical synthesis is limited. It's important to choose a suitable substance to extend the solubility of organic compounds in water. The aim of this work is to develop the studies of using water as alternative reaction media for traditional volatile organic solvents in organic synthesis.This thesis is divided into five chapters.Firstly, one brief introduction about the concept, the significance, the target and the focal point of the Green and Sustainable Chemistry was introduced. Then a brief introduction of several alternative reaction media, including Ionic Liquids, the Fluorous Media, Supercritical Fluids and Water, as well as the progress in several classical reactions taken in aqueous media was also reviewed.Secondly, the Suzuki cross-coupling reaction of aryl halides and sodium tetraphenylborate in PEG400 solution catalyzed by PdCl₂ was studied. The research results showed that the Suzuki cross-coupling reaction proceeded smoothly in PEG4OO/H₂O solution, the procedures are simple, the yields are excellent, the product purifications are convenient and environmentally benign. We envisage that PEG400 not only acted as an efficient solvent media and a phase transfer catalyst (PTC), but also a stabilizer for the Pd catalyst. The reaction system can be reused after workup.Thirdly, the condensation of aryl aldehydes and Rhodanine in water media catalyzed by Polyethylene Glycol (PEG) 400 was studied. The research results showed that the reactions proceeded smoothly in water, the procedures are simple, the yields are excellent, the product purifications are convenient and environmentally benign. We envisage that PEG400 not only acted as an efficient solvent media, but also as a phase transfer catalysts (PTCs).