tert-Butylsulfinyl-fluoroacetate: versatile reagent for the preparation of fluoroethylidenoate derivatives

The preparation of (Z)-α-fluoroalkenoates from readily available methyl-tert-butylsulfanyl- or tert-butylsulfinylfluoroacetate or is described. This short synthesis, based on a direct extrusion of SO2 from β-hydroxysulfoxides, presents a moderate to high selectivity and affords (Z)-α-fluoroalkenoates in 40–81% overall yields without purifications of the intermediates. This procedure was applied to functionalised aldehydes and ketone. The mechanistic aspect of the reaction was also discussed.