Methodological Study On Benzothiophene Synthesis And Propargyl Alcohol Rearrangement

Propargylic alcohols and their derivatives are versatile synthetic intermediates,which have been widely applied in modern organic synthesis.Recent advances reveal that propargylic alcohols and their derivatives could undergo the Meyer-Schuster rearrangement and Rupe rearrangement with the help of Lewis acids,enabling the production of a wide array of intricate and valuable organic molecules via cascade reactions.In view of this special property of propargylic alcohols and their derivatives,the rearrangement reactions of propargylic alcohols and their derivatives have proven to be powerful strategy to forge carbocycles and heterocycles.Therefore,much attention has been paid to the cascade rearrangement of propargyl alcohols,which is also the research content of this dissertation.Benzothiophene and its derivatives have attracted tremendous attention due to their wide application in pharmaceuticals,material sciences,catalysis and biology.As a consequence,a myriad of reports has been developed for the preparation of substituted benzothiophenes.In recent years,radical cascade reaction has been predominant for the synthesis of benzothiophenes,since it offers a simple and efficient approach to build these skeletons.Benzoselenophenes have also attracted tremendous attention owing to their wide application in organic synthesis,medicinal chemistry,and materials science.This paper mainly includes the following three aspects of work:1.The synthesis of terpenoids via rearrangement of propargyl alcohols.Terpenoids are widespread found in natural products,which are also the core framework of many bioactive molecules.The rearrangement of propargyl alcohol produces a olefinic carbon cation to form an enol.With the assistance of oxidant,a series of terpenoids compounds are synthesized via the radical cyclization reactions.The current reactions demonstrates a wide range of substrate,which could provide a simple and efficient route for the construction of terpenoids.2.The synthesis of benzothiophenes via rearrangement of propargyl alcohols.Under the oxidative conditions,the 3-(2-(methylthio)phenyl)-1,1-diphenylpropan-2-yl-1-ols could undergo the Meyer-Schuster rearrangement reaction,which enables to produce a series of benzothiophene compounds via intramolecular radical cascade reaction.3.Photocatalysed synthesis of benzothiophenes.Visible-light-induced redox reactions have emerged as formidable tool in synthetic chemistry.In this reaction,benzene sulfonyl chloride could form the benzene sulfonyl radical with the visible-light,which further undergoes the radical cyclization reaction to afford a round of 3-sulfonylbenzothiophenes.The current method features mild conditions,simple operation,good functional group tolerance,good yields and so on.