Research On The Reactivity Of Oxidative Cross-coupling Between Organozirconium And Alkynylcopper Reagents

Organometallic Chemistry as a interdiscipline of organic chemistry and inorganic chemistry, is an important part of modern organic chemistry. Oxidative coupling reaction of two organometallic reagents as a new type of building carbon- carbon bonds reaction mode has become a research focus in the field of Organometallic Chemistry, which is because of its wide scope of substrates and high atomic-economy. The research of oxidative coupling of two organometallic reagents is mainly focused on the main group metals or metalloids, while the research of early transition metal is relatively less. What’s more the selectivity of this reaction is difficult to control and potential side reactions could occur in the oxidative coupling reactions including homocoupling of organometallics and direct reaction of the organometallic reagents with oxidant Over the past few decades, the early transition metal, especially the zirconium reagents, plays an important role in the field of organometallic chemistry, especially in the field of organometal catalyzed new synthesis methods. Since oxidative coupling reaction of organometallic reagents has a great potential in chemical bond formations, this paper focuses on developing new type of oxidative coupling reaction and investigating the relevant mechanis, we are mainly studied oxidative coupling between early transition metals zirconium and cuprous acetylene,.After a series of experiments on the optimization of conditions, we have accomplished this reaction to selective synthesis the multisubstituted enynes and carboatomic ring without catalysts and external oxidants. To the best of our knowledge, this is the first external oxidant-free procedure for oxidative cross-coupling of two different organometallic reagents without the formation of any homocoupling products. This paper mainly includes the following three parts.Part I: In this part, the oxidative coupling reaction and the development of the oxidative coupling of two organometallic reagents was presented,.Part II: We studied the reaction of alkenylzirconocene with cuprous acetylene, afte a series of experiments on the optimization of conditions, including reaction temperature, additives and oxidants, we found that the reaction proceeded succcessfully in the presence of pyridine at 50 oC to get the multisubstituted enynes with high selectivity in good yields. What’s more we didn’t find any homocoupling products in this reaction. This oxidative reaction can conduct under mild conditions with a wide range of substrates. These products can be characterized by NMR spectra.Part III: The reaction of of zirconacycles with electrophilic reagents generating carboatomic ring has been systematically researched, but there are few reports about the reaction by using the organometallics to react with zirconacycles. We studied the reaction of zirconacycles with cuprous acetylene. A series of cyclic compounds were obtained and the structure of the products was characterized by NMR spectra and the configuration of the products can be confirmed by a two-dimensional NMR spectra and single-crystal X-ray.