Synthesis Of Tetrahydroquinoline Derivatives Via Rhodium Catalyzed Intramolecular Cyclopropanation Reaction Of N-sulfonyl-1,2,3-triazoles

As an active intermediate usually derived from diazo compound,stable metal carbene was widely used in organic synthesis.In recent years,N-sulfonyl-1,2,3-triazole has become an alternative precursor for the formation of metal carbene.Under the catalysis of rhodium?Rh?,N-sulfonyl-1,2,3-triazole could be converted to?-imino carbene,which could undergo various typical carbene reactions,for example,cyclopropanation,1,2-shift,C-H,O-H or N-H insertion,and so on.However,unlike carbonyl carbene,the increased nucleophilicity of the nitrogen atom of?-imino carbene provides higher synthetic flexibility,making it much easier to react with olefin,alkyne,nitrile,isocyanate,aldehyde,furan and hydrazine to produce various useful nitrogen-contained heterocycles.The main content of this dissertation is Rh catalyzed intramolecular cyclopropanation of N-sulfonyl-1,2,3-triazole producing tetrahydroquinoline compound.In this thesis,a series of N-sulfonyl-1,2,3-triazoles were synthesized starting from different substituted o-aminobenzoic acids.Then under nitrogen atmosphere,with 5 mol%of Rh₂?piv?₄ as catalyst,1,2-dichloroethane as solvent,N-sulfonyl-1,2,3-triazole could be converted to cyclopropane-fused tetrahydroquinolines intramolecularly at 50°C with satisfactory yields.A plausible reaction mechanism was suggested.The reaction tolerated common functional groups under mild conditions and side reactions,such as 1,2-shift and C_sp2-H insertion,were avoided completely.The targeted product could be transformed to some other cyclopropane-fused tetrahydroquinoline compounds easily,illustrating the potential of this procedure in organic synthesis.