Rhodium-Catalyzed C-H Bond Alkylation Of Triazole Derivatives

Transition-metal catalyzed C-H bond activation has become an important protocol for the construction of carbon-carbon bonds(C-C)and carbon-heteroatom(C-X,X =N,Cl,Br,I,etc.)bonds in organic synthesis due to its simple operation,high efficiency and environmental protection.In this paper,rhodium-catalyzed alkylation of triazoles by using diazo compounds as the alkylation reagents was described.A number of mono-and disubstituted triazole derivatives were selectively obtained.The first chapter introduces the recent development of the synthesis of triazole derivatives and transition-metal catalyzed 1,2,3-triazole-assisted C-H functionalization,the synthetic routes including transition-metal catalyzed 1,3-dipolar cycloaddition,none metal-catalyzed 1,3-dipolar cycloaddition,annulation reactions involving the starting materials other than alkynes are summarized.In addition,transition-metal-catalyzed triazole-directed C-H arylation,alkynylation,alkenylation,alkylation,acylation,alkoxylation,amination and halogenation reactions are also reviewed.In the second chapter,we described a facile and efficient way to synthesize triazole derivatives.We found that under mild reaction conditions,the combination of[Cp*RhCl2]2 and AgSbF6 could catalyze ortho C-H alkylation of triazoles using diazo compounds as the alkylating reagents.Various alkylated triazoles were obtained in good to excellent yields.When the amount of diazo substrate was 2.2 equivalent and the reaction time was 12 h,aryl ortho dialkyl-substituted triazole derivatives were obtained in 25-96%yields.When the amount of diazo substrate is 1.2 equivalent and the reaction time is 2 h,the monosubstituted products can be obtained in 26-95%yields.The alkylation is simple and practical,providing an efficient and rapid protocol for the synthesis of triazole derivatives.