The Studies Towards The Application Of Directed Lithiation On Direct Arylation And The Preparation Of Benzoisothiazoles

The study towards functionalization of arenes is popular in organic synthesis.This thesis mainly introduces the directed lithiation and further application of arenes,including the transmetallation-cross-coupling reaction of organolithium reagents to achieve direct arylation,as well as the cyclization reaction to prepare benzoisothiazoles.In chapter 1,we talk about the development of the research about lithiation reactions and their application in recent years.The introduction is from three parts: DoM reaction,transmetallation cross-coupling reaction of organolithium reagent and the preparation of dilithium compounds.In chapter 2,we introduce the DoM reaction and further transmetallation cross-coupling reaction of anisole,which can tolerate a series of aryl halides,and can be applied to aniline,benzylamine and phenylthioether as well.Therefore,this will provide an alternative strategy for the direct arylation of a range of anisoles,thioethers and anilines.In chapter 3,we introduce a noval trilithium complex of thioanisole and the study of its preparation,separation,X-ray characterization and synthetic application.We developed a cyclization strategy of the trilithium molecule and nitriles to afford benzoisothiazoles with moderate to good yields.This type of reaction can tolerate a series of nitriles,which can provide a new pathway for the construction of S-N bond in chemical synthesis.