Johnson-Claisen rearrangement of gamma-fluoro-gamma-(di-or tri-fluoromethyl)allyl alcohols affording stereoselective access to deta-fluoro-deta-di- or tri-fluoromethylated gamma,delta-unsaturated carboxylic acid esters

摘要

Gamma-Fluoro-gamma-di- or tri-fluoromethyl-deta-(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 deg C for 24 h or 48 h to afford the corresponding (Z)-deta-fluoro-deta-polyfluoromethyl-gamma,delta-unsaturated carboxylic acid esters in fair to good yields.