Fluorination of Orthothioesters through Oxidative Desulfurization-Fluorination

Article abstract of DOI:10.1246/bcsj.71.1939

The oxidative desulfurization-fluorination of orthothioesters of type RCH₂C(SMe)₃ using n-Bu₄NH₂F₃ and 1,3-dibromo-5,5-dimethylhydantoin gave bromodifluorination products RCHBrCF₂SMe in good yields. The products were converted into bromodifluoro olefins RCBr=CF₂ via oxidation and thermolysis. In a similar way, the orthothioesters of type RCH(OH)C(SMe)₃ or RCH(OAc)C(SMe)₃ were fluorinated to afford difluoro ketones RCOCF₂SMe or difluoro acetates RCH(OAc)CF₂SMe, respectively. The difiuoro acetates were reduced to RCH(OAc)CF₂H by radical reduction. The mechanisms are discussed for difluorination accompanied by bromination or oxidation.