Manganese Catalyzed C–H Bond Activation Of Indoles And The Synthesis Of Carbene Silver Polymer

Since atomic economy chemistry being put forword by the American chemist Barry M Trost in 1991, it has become the focus in organic synthetic methodology research. From the perspective of sustainable development,the atom economy chemistry is one of the most important challenges and opportunities of modern chemistry. Based on thses concepts of manganese catalyzed C–H activation of indoles to synthesize multisubstituted alkenes or carbazoles, and we also designed and synthesized new polymer carbene silver catalyst. Some progress has been made in these fields.By using the MnBr(CO)5 as the catalyst, indoles with nitrogen directing group and alkynes as raw materials, the manganese catalyzed addition reaction of indole with alkyne in the presence of catalytic amount of benzoic acid has been realized, with a series of indole olefins compounds as the product. And the directing group can be removed easily to give N–H indole olefins. Based on the research of the mechanism, it is considered that the first step is manganese catalyzed indole C2–H bond cleavage with the formation of five membered ring of Mn-complex. Then the Mn-complex reacted with alkynes to generate the product indole olefins and the benzoic acid has played a very important role for the transfer of hydrogen in the process.Based on the study of indole olefins, the manganese catalyzed [2+2+2] cycloaddition reaction has been realized. With the indoles and alkynes as the raw materials, a series of multisubstituted carbazole compounds has been synthesized, which can react with alkali to remove the directing group with the formation of N–H carbazole. The experimental research showed that the five membered ring Mn-complex was first formed in the reaction which coud react with alkyne generating carbazole with the release of hydrogen.In order to better realize the sustainable development of chemical, we designed and prepared a new recyclable N-heterocyclic carbene silver(NHC-Ag) polymer catalyst. The obtained polymer was characterized by infrared spectrum, N2 adsorption and desorption analysis and thermogravimetric analysis. The polymer had good thermal stability and large specific surface area. The N2 adsorption and desorption analysis experiment showed that the polymer was a microporous material.