Nickel-catalyzed C-S Bond Forming Reductive Cross-coupling

The sulfur element is located in the main group Ⅵ of the third cycle of the periodic table,belonging to the oxygen group element.Sulfur-containing compounds exhibit diverse physical and chemical properties due to their diverse valence states,which have been widely used in organic synthesis and pharmaceutical research.For example,as a broad-spectrum antibiotic,penicillin is used to prevent and treat wound infections.However,the quantities and types of natural sulfur-containing compounds are relatively limited.Therefore,the construction of sulfur-containing structure is an important component in organic synthesis.In the past few decades,chemists have developed a series of methods to achieve the synthesis of sulfur-containing molecules.Including(1)introducing sulfur atoms or sulfur-containing groups into molecules;(2)functional modification of sulfur-containing building blocks.It should be noted that the building blocks formed by a carbon atom simultaneously linked to sulfur and other functional groups/heteroatoms are common in drug molecules,Iliparcil,an antithrombotic drug,for instance,contains structural units of 0,S-acetals.Therefore,the versatile functionalization on α-position of sulfur-containing compounds weights a significant research value..In this dissertation,we developed two synthesis methods to construct carbon sulfur bonds.A series of α-functionalized thioethers was attained via nickel-catalyzed reductive coupling strategy,using thiosulfonates as sulfuration agents.The dissertation is mainly divided into the following three parts:Chapter 1 Research BackgroundIn this chapter,we briefly introduce the application examples of sulfur containing compounds in the field of pharmaceutical chemistry.After that,we summarized the construction of carbon sulfur bonds,mainly introducing the catalytic coupling reactions between sulfuration reagents and organic molecules.Finally,based on the investigation of the literature,the reaction design was proposed.Chapter 2 Synthesis of α-CF3 Thioethers via Nickel Catalyzed Reductive CouplingIn this chapter,the synthesis of α-CF3 thioethers have been achieved via nickel catalyzed reductive coupling,using trifluoromethylated alkyl bromides as substrates and thiosulfonates as sulfuration agents.The reaction demonstrated excellent catalytic activity and chemical selectivity with good substrate compatibility under mild conditions.Mechanism studies proved that the reaction might undergo a radical process.Chapter 3 Synthesis of O,S-Acetals via Nickel Catalyzed Reductive CouplingIn this chapter,the synthesis of O,S-acetals have been achieved via nickel catalyzed reductive coupling,using alkyl α-bromobenzoates as a substrates and thiosulfonates as sulfuration agents.The reaction represented a good chemical efficiency and wide substrate compatibility under mild conditions.