Study On The Synthesis Of Bridged Heterocycle Via 1,3-Sulfinate Migration-Cyclization Reaction

N-sulfonyl-1,2,3-triazole can be converted intoα-imino rhodium carbene by the catalysis of rhodium metal.Due to electrophilic carbene carbon and nucleophilic imine nitrogen,α-imino rhodium carbene could participate in various chemical reactions as 1,3-dipole synthon,such as X-H（X=C,N,O）insertion,cycloaddition,migration reaction,etc,and can be widely used in the synthesis of bioactive nitrogen containing heterocycles.In this thesis,bridged heterocycles were synthesized by rhodium carben-induced migration-annulation strategy.In this thesis,we designed and synthesized triazoles containing aldehyde and sulfinate groups,which were converted to the correspondingα-imino rhodium carbene under rhodium catalysis,the following 1,3-sulfinate migration yielded zwitterionic intermediate,whose carbon cation part was captured intramolecularly by aldehyde group.Cyclization of the newly formed zwitterion provided N,O-heterobridged cycle as desired product.The optimized reaction conditions were as follows:under nitrogen atmosphere,2 mol%Rh₂（piv）₄as catalyst,1,1,2-trichloroethane as solvent,heated at 110 ^oC.Scope invastigation revealed that a series of N,O-heterobridged cycles were obtained in medium to good yields,and the reaction beared good functional group tolerance,chemical and stereoselectivity.Moreover,the functional group can carry out a variety of transformations.The migration-cyclization strategy in this thesis provides greater flexibility for the synthesis of heterocyclic compounds,especially for the construction of polycyclic compounds with complex skeleton.