Copper-Catalyzed Reaction Of 3-diazoindolin-2-imines

As a very important kind of organic compounds,3-diazoindolin-2-imines are valuable precursors of metal-carbenes to participate in many reactions. In this dissertation, we investigated the reactions between 3-diazoindolin-2-imines and indoles or non-terminal alkynes using copper (?) as catalyst. The results are summarized as below.(1) We developed a Cu(OTf)2-catalyzed reaction of 3-diazoindolin-2-imines with indole derivatives under oxygen conditions, which formed 3,3-diaryl-indole-2-imines. The cascade process involves a C-H insertion of indole on the electron-deficient copper carbene which was derived from the copper-catalyzed decomposition of 3-diazoindolin-2-imine, and a copper-catalyzed C-C cross coupling. This method has several advantages, such as easily available reactants, simple conditions. In addition, it also has wide substrate scope with good yields. In addition,3-arylindolin-2-amines could also be approached by controlling the amount of reactants and the reaction conditions.(2) We developed a synthesis of pyrrolo[2,3-b]indole derivatives from 3-diazoindolin-2-imines and non-terminal alkynes using Cu(OAc)2 as catalysts. The reaction proceeded via a [3+2] cycloaddition and produced pyrrolo[2,3-b]indoles in good to excellent yields (20 examples,45-99% yields). In consideration of our previous works on the reactions between 3-diazoindolin-2-imines and terminal alkynes using Rh2(Oct)4 as catalysts, which was not suitable for the non-terminal alkyne substrates, this methodology should be an essential extension of our work on 3-diazoindolin-2-imine chemistry.