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 difluoro acetates were reduced to RCH(OAc)CF2H by radical reduction. The mechanisms are discussed for difluorination accompanied by bromination or oxidation.
使用n-Bu_4NH_2F_3和1,3-二
溴-5,5-二甲基乙内酰
脲对RCH_2C(SMe)_3类型的原
硫酯进行氧化脱
硫氟化反应,以良好收率得到了
溴二
氟化产物R
CHBrCF_2SMe。通过氧化和热解,产物被转化为
溴二
氟烯烃RCBr=CF_2。类似地,RCH(OH)C(SMe)_3或RCH(OAc)C(SMe)_3类型的原
硫酯被
氟化,分别得到二
氟酮RCOCF_2SMe或
二氟乙酸酯RCH(OAc)CF_2SMe。
二氟乙酸酯通过自由基还原被还原为RCH(OAc)CF_2H。讨论了伴随
溴化或氧化的二
氟化反应机理。