Base-Catalyzed Intramolecular Defluorination/O-Arylation Reaction For The Synthesis Of 3-Fluoro-1,4-Oxathiine 4,4-Dioxide

A novel process involving base-catalyzed intramolecular defluorination/O-arylation of readily available alpha-fluoro-beta-one-sulfones was realized and provided a series of 3-fluoro-1,4-oxathiine 4,4-dioxide derivatives in good to excellent yields. Unlike traditional defluorination reactions with stoichiometric base as the deacid reagent, this process is triggered by a catalytic amount of base (TMG: tetramethylguanidine) and molecular sieves serve as both an adsorbent to remove HF acid and an activator to assist C-F bond cleavage.