Study On The Construction Of Benzothiophene Derivatives Based On Controllable Tandem Reaction

In recent years,benzothiophene and its derivatives have played an important role in organic semiconductor materials,pesticides,and the treatment of certain diseases,such as leishmaniasis,and have received increasing attention from researchers.Therefore,an efficient and economical method for synthesizing such compounds is urgently needed.After studying the existing literature,we found that MBH carbonate has an irreplaceable position in the construction of C-C bonds and complex cyclic compounds.Therefore,we used thioaurones and MBH carbonate to construct a series of compounds with benzothiophene skeleton.On the other hand,due to the similarity in structure and properties of allene and MBH carbonate,we have also studied the former.The research work of this thesis mainly includes the following aspects.1)We synthesized a series of thioaurones from various substituted thiophenols,and completed the cyclization reaction under the catalysis of PPh₃ in THF.This is the first[4+2]cyclization reaction in which MBH carbonate is directly promoted by the organic small molecule phosphorus and the MBH carbonate acted as two-carbon synthon.In addition,the reaction is simple in operation and good in applicability,and a series of benzothiophene fusedα-pyran derivatives are efficiently synthesized.2)During the optimization of the first[4+2]annulation reactions,we found that[4+3]cyclization reaction between thioaurones and MBH carbonate occurred when EtOH was used as the reaction solvent.The reaction is also simple to operate,mild in conditions and good in applicability,and can efficiently synthesize a series of 2,3-dihydrooxacycloheptene derivatives.3)We also reacted thioaurones with MBH carbonate in DMF and obtained a new compound.The reaction has good applicability and can efficiently synthesize a series of oxatricyclodecene derivatives.4)We have also studied the reaction between thioaurones and allene.The cyclization product of[4+2]was obtained with higher yield and regioselectivity.A total of 81 benzothiophene derivatives were synthesized in this thesis.Their structures were characterized by nuclear magnetic resonance,infrared,high resolution mass spectrometry and melting point determination（solid）data.The representative compounds were characterized by X-ray single crystal diffraction.Representative compounds were confirmed by X-ray single crystal diffraction.