Decarboxylative Radical Coupling Of Arylthiodifluoroacetic Acids And Ethynylbenziodoxolone(EBX)

Sulfur and fluorine are both leading constituents of the pharmaceuticals.Recently,there has been increasing interest in functional groups that contain fluorine and sulfur atoms.To modify the properties of organic molecules,new fluorinated substituents are continuously being developed.The arylthiodifluoromethyl(Ar SCF₂)group has been widely used in the fields of drug discovery and material science.In addition,the Ar SCF₂group is a general precursor for the preparation of other fluorine-containing moieties such as difluoromethyl,difluoromethylene and difluoroalkyl.Various methods have been reported for the preparation of Ar SCF₂-substituted alkanes and arenes.In comparison,the synthesis of Ar SCF₂-substituted alkenes and alkynes remains less explored.In this thesis,we developed a practical and efficient approach to Ar SCF₂-substituted alkynes through the radical coupling reaction of readily available arylthiodifluoroacetic acids and ethynylbenziodoxolone(EBX)reagents.Under transition metal-free conditions,aryl-substituted EBXs were converted to the corresponding Ar SCF₂-substituted alkynes in moderate to good yields,whereas TIPS-EBX underwent silver-catalyzed decarboxylative conditions to deliver the desired coupling products.