The reaction of ethyl α-bromocinnamates with tetrabutyl ammonium fluoride(TBAF) was influenced largely by the position of the substituent at the phenyl ring.While the substrates without an ortho substituent at the phenyl ring were transformed to the corresponding β-fluoro ethyl cinnamates under the reaction conditions,the presence of an ortho substituent only resulted in the formation of ethyl 3-phenylpropiolate derivatives.The reaction of ethyl 2-bromo-3-(4-methoxyphenyl) acrylate also failed to deliver the hydrofluorination product due to the electron-donating effect of the methoxy group. The reaction of ethyl α-bromocinnamates with tetrabutyl ammonium fluoride (TBAF) was specified largely by the position of the substituent at the phenyl ring. Whilst the substrates without an ortho substituent at the phenyl ring were transformed to the corresponding β-fluoro ethyl cinnamates under the reaction conditions, the presence of an ortho substituent only resulted in the formation of ethyl 3-phenylpropiolate derivatives. The reaction of ethyl 2-bromo-3- (4-methoxyphenyl) acrylate also failed to deliver the hydrofluorination product due to the electron- donating effect of the methoxy group.