Study On The Tandem Reaction Between Allylic Sulfur Ylides And Thioaurones

Tandem reaction is a chemical process that comprises at least two consecutive reactions such that each subsequent reaction occurs only in virtue of the chemical functionality formed in the previous step.This type of reaction has the advantages of simplifying the operation and reducing the emission,and it can rapidly and efficiently construct a compound with a variety of structures,skeletons and configurations from a relatively simple raw material in one step.Therefore,it occupies an important position in organic synthesis chemistry.Sulfur ylide,on the other hand,is a class of highly reactive substances.As an important intermediate for organic synthesis,it is widely used in various tandem reactions to efficiently construct a wide range of carbocyclic and heterocyclic compounds.Therefore,this thesis would focus on exploring the tandem reaction based on allylic sulfur ylide and efficiently constructing benzothiophene-fused oxygen-containing heterocyclic compounds.The main work is divided into the following aspects:1)A series of thioaurones were synthesized from the substituted thiophenols,and the[4+3]tandem annulation reaction was developed with allylic sulfur ylide promoted by NaH.In this reaction,allylic sulfur ylide acted as a three-carbon synthon,and benzothiophene-fused oxygen-containing cycloheptane derivatives were synthesized.Higher yields and mild conditions made the reaction potentially useful for the synthesis of oxa-seven-membered ring compounds.2)Based on the above work,when we replaced the aryl substituent on the end of the double bond of thioaurone with an ester or ketone.The[4+2]tandem annualtion reaction was occurred with allylic sulfur ylide catalyzed by Cs₂CO₃.This is the first reaction of allylic sulfur ylide acted as a two-carbon synthon.3)During the optimization of the first[4+3]annulation reactions,we were surprised to find that a new compound was formed after lengthening the reaction time when tertiary amine as a base.Through the detailed optimization of the reaction conditions,we found that when DIPEA was used as a base and anhydrous CH₂Cl₂ as a solvent,the reaction produced a pair of benzothiophene-fused dihydropyran derivatives,and the sulfide in the sulfur ylide was also introduced into the products.Moreover,allyl sulfur ylide also acted as a two-carbon synthon in the reaction.A total of 71 novel compounds were synthesized in this thesis.All of the new compounds were characterized by ¹H NMR,¹³C NMR,IR,HRMS,m.p.?solid?.Some of the compounds were confirmed by X-ray single crystal diffraction.