Study On Transition-metal-catalyzed Ring Opening/cyclization Tandem Reactions Of Carbocyclic Compounds

Carbocyclic compounds in cyclic compounds are an important class of cyclic compounds composed of carbon atoms.Small cyclic compounds have great angular tension due to their ring structure.For example,the carbon-carbon bond in ternary carbocyclic compounds(cyclopropane derivatives)and quaternary carbocyclic compounds is unstable,which is easy to break and open ring.A large number of complex compounds substituted by different functional groups can be obtained by ring opening/cyclization series reaction.There are many reported ring-opening and cyclization tandem reactions of carbocyclic compounds,which are mainly catalyzed by expensive transition metals such as Pd,Rh,Ru,Au or strong Lewis acid,and are limited in practical application.In this paper,the development of cheap transition metal-catalyzed ring opening/cyclization tandem reactions of carbocyclic compounds is studied,which includes the following contents:(1)A novel and effective bifunctional reaction method of oxidized C-C?-bond between methyl cyclopropane and?-keto acid promoted by silver was realized.A series of 2-acyl-substituted 3,4-dihydronaphthalene derivatives were synthesized in50%-87%yield by using Ag NO₃ as catalyst,K₂S₂O₈ as oxidant,DMF as solvent and argon at 50?for 24 h.The reaction provides a mild and simple strategy for the acylation/arylation of carbon.Two new C-C bonds are constructed by combining the C-C?-bond with an acyl group and an aromatic ring bond.(2)To develop a convenient method for promoting cyanomethylation/ring expansion of vinyl cyclopropane with?-C(sp³)-H bond in alkyl nitrile by copper.In the reaction,a series of 1-cyanoethylated 3,4-dihydronaphthalene compounds were synthesized at 53%-83%yield by using Cu(OAc)₂ as catalyst,Ag₂CO₃ as substrate and alkyl nitrile as solvent at 120 ^oC under argon.The cyanomethylation/ring expansion involves free radical pathway,and carries out cyanomethyl radical formation,free radical addition and ring expansion.In this catalytic system,one C-C bond is broken and two new C-C bonds are formed.(3)Iron-mediated radical cyanoalkylsulfonylation/arylation of active olefins with cycloketone oxime derivatives via cleavage of C-C single bond and insertion of SO2is developed for the preparation of cyanoalkylsulfonylated oxindoles.In the method,cheap and easily available Fe Cl₂ is used as a catalyst,Na₂S₂O₅ as sulfur dioxide source,CH₃CN is used as a solvent,and a series of cyanoalkylsulfonylated indolone derivatives are synthesized at a yield of 44%-74%under argon for 12 h.The reaction conditions are mild,and the application range of substrates is wide.