Johnson–Claisen rearrangement of γ-fluoro-γ-(di- or tri-fluoromethyl)allyl alcohols affording stereoselective access to β-fluoro-β-di- or tri-fluoromethylated γ,δ-unsaturated carboxylic acid esters

γ-Fluoro-γ-di- or tri-fluoromethyl-β-(tosyloxy)allyl alcohols smoothly reacted with the orthoacetic acid triethyl ester in the presence of a catalytic amount of propionic acid and hydroquinone at 140 °C for 24 h or 48 h to afford the corresponding (Z)-β-fluoro-β-polyfluoromethyl-γ,δ-unsaturated carboxylic acid esters in fair to good yields.