Base-Catalyzed Intramolecular Defluorination/O-Arylation Reaction to Synthesis of 3-Fluoro-1,4-oxathiine 4,4-dioxide

A novel process involving base catalyzed intramolecular defluorination/O-arylation of readily available α-fluoro-β-one-sulfones was realized that provided a series of 3-fluoro-1,4-oxathiine 4,4-dioxide derivatives in good to excellent yields. Different from the traditional defluorination reactions by using stoichiometric base as deacid reagent, this process is triggered by catalytic amount of base as catalyst and molecular sieve serves both as adsorbent to remove HF acid and activator to assist C-F bond cleavage.