Study On The Domino Reactions Of In Situ Generated C=N Double Bond

As a kind of important functional groups, C=N double bond is widely used for the total synthesis of nature products, the construction of heterocycles and functional materials. In this thesis, the formation of C=N double bond and the reactions it is involved in are reviewed. The systems of activated amide and N-sulfonyl ketenimine are explored, in which the C=N double bond are generated in situ, and several valuable compounds are synthesized. The discussions and results are listed as following:1. The self-dimerization of amides under the condition of trifluoromethanesulfonic anhydride (Tf2O) and2-chloropyridine (2-ClPy) is established, and multi-substituted amidines are synthesized. Then we induced the intermolecular reaction into intramolecular, symmetric benzimidazoles, unsymmetric benzimidazoles, pyrimidine derivatives and isoindol-1-one derivatives are constructed.2. The copper bromide catalyzed multi-component reactions of2-methylindole, sulfonyl azides and terminal alkynes under argon atmosphere is achieved, furnishing3-functional indole derivatives I. When we do this reaction under oxygen atmosphere, a four component domino reaction involves2-methylindole, sulfonyl azides terminal alkynes and oxygen occurs, and we get the oxidative product of compound I-another3-functional indole derivatives Ⅱ. Then we propose a copper-cascade catalysis mechanism, and we could obtain2,3’-biindolyl and cyclopenta[b]indole skeletons after one single steps conversion of some special products.