Studies On Photoinduced Disulfuration Reactions

Unsymmetrical disulfides refer to compounds containing disulfide bonds and connecting different groups on both sides of disulfide bonds.They are widely existed in fields of food chemistry,pharmaceutical,natural product chemistry,functional material and others,they also play a crucial role in these fields.Therefore,the simple,fast and efficient synthesis of unsymmetric disulfides has attracted broadly attention.So far,unsymmetrical disulfides can be synthesized in two ways: one is the strategy of constructing S-S bond,and the other is the strategy of building C-S bond.The former method to access unsymmetrical disulfides includ oxidation coupling,nucleophilic substitution,and disulfide exchange.These S-S bond-forming approaches are often hampered by largely unavoidable homocoupling reactions and overoxidation.In an attempt to address these issues,great efforts of chemists have focused on the development of prefunctionalized disulfurating reagents to introduce disulfides moieties via C-S bond formation.With the help of disulfurating reagents,chemists have achieved this process through nucleophilic or electrophilic substitution reactions and cross-coupling reactions.In recent years,the rapid development of radical chemistry has provided a new thought for the synthesis of unsymmetric disulfides.In this paper,we have developed a series of radical methods for the synthesis of unsymmetric disulfides.The thesis is divided into five chapters,which are summarized as follows:The first chapter : The importance of unsymmetric disulfide and its synthesis.In this chapter,the structural characteristics of unsymmetric disulfide and its applications in related fields are introduced,and the synthesis methods of unsymmetric disulfide in recent years are summarized.The second chapter: Study on visible light induced dithiosulfonylation of alkenes and alkynes and other substrates.In this chapter,we introduce the dithiosulfonylation of alkenes,alkynes,and other substrates by using dithiosulfonate through atom transfer radical addition pathway.The reaction has the characteristics of redox neutral,mild reaction conditions,wide substrate scope and so on.We accomplished the introduction of disulfide bond into alkenes,alkynes and other substrates using th is method,which has greatly expanded the substrate scope of dithiosulfonylation reactions.The third chapter: Study on nucleophilic disulfuration reaction.In this chapter,we introduce the nucleophilic disulfuration in which the product of dithiosulfonyl ation of styrene is uesd as a novel disulfurating reagent.The disulfide anions produced in situ by this reagent in the presence of base can achieve the dehalogenated disulfide reactions of many alkyl halides and pseudohalides by nucleophilic substitution.In addition,the disulfide anions formed in situ can also be used as nucleophiles for ring-opening of epoxides and the addition of Michael acceptors.The fourth chapter: Study on photocatalytic C-H disulfuration of inactive alkanes and aldehydes.In this chapter,we report a photocatalyzed hydrogen atom transfer strategy to realize the intermolecular disulfuration of inactive alkanes,furthermore,this approach can be extended to aliphatic aldehyde,aryl and heteroaryl aldehydes to achieve their disulfuration under mild conditions.The late-stage modification of complex molecules is successfully achieved through this method,rendering the approach highly valuable.The fifth chapter: Study on visible light induced dithiotrifluoromethylation of unactive alkanes.In this chapter,we combined with Langlois reagent and dithiosulfonate to achieve the simultaneous introduction of trifluoromethyl and disulfide group into unactivated olefin substrates through photo-induced multicomponent reaction.The reaction has the characteristics of wide substrate scope,good functional group tolerance and so on,which can also realize the late-stage modification of many natural products.The simultaneous introduction of trifluoromethyl and disulfide bonds makes it possible to di scover new drugs.