Studies On Copper-Catalyzed Cycloaddition Of Alkynes And Azides To Construct Fully Substituted 1,2,3-Triazoles

Fully substituted 1,2,3-triazoles are a very important class of nitrogen-containing heterocyclic compounds and play an increasingly important role in many fields such as the improvement of original drugs or the research and development of new drugs,the conjugation with biomolecules,and the establishment of lead compound libraries.The copper-catalyzed 1,3-dipolar cycloaddition of terminal alkynes and organic azides has the advantages of high yield,good regioselectivity,fast reaction rate,universality and reliability,etc.Therefore,the multi-component cascad cycloaddition reaction developed on the basis of the Cu AAC reaction has become a powerful method for the construction of fully substituted 1,2,3-triazole compounds.But at present,this way is relatively singleness in the types of substituent structure of the product and reaction modes.Therefore,it is a very significant work for developing the cascade reaction based on Cu AAC to construct fully substituted 1,2,3-triazole compound with functional and structural diversity.This thesis is composed of three parts:(1)The research progress of construction fully substituted 1,2,3-triazole were reviewed.It was mainly classified and narrated by the types of alkynes(internal alkynes,terminal alkynes and propiolic acids).(2)Copper-catalyzed decarboxylation and cycloaddition to construct 5-arylated1,2,3-triazoles.Arylboronic acids were employed as 5-aromatic sources to interrupt the cuprate–triazole intermediate of copper-catalyzed decarboxylation of Propiolic acids and azide formation to successfully construct the fully substituted 1,2,3-triazoles.This reaction featured a wide substrate scope,mild reaction conditions,readily available starting materials,operational simplicity,and used molecular oxygen as the oxidant.(3)Copper-catalyzed 1,3-dipolar cycloaddition/cascade reaction to construct diverse 5-seleno-or 5-thio-triazoles.Two carbon-selenium or carbon-sulfur bonds were successfully constructed between the 5-position of 1,2,3-triazoles and the epoxides by the ring-opening of epoxides,starting from selenium powder or potassium sulfide.This reaction features mild conditions,readily available and broad-scope substrates,good functional group compatibility,high efficiency and regioselectivity,easy operation.