cis-and trans-Isomers of derivatives of 3-halogenoacrylic acids undergo nucleophilic displacement reactions with triphenylphosphine, tri-n-butylphosphine, and triethyl phosphite to produce the correspondingtrans-vinyl-phosphonium salts and-phosphonates exclusively. 1H nmr spectra are reported for these compounds. The mechanism of the displacement reaction is discussed.
![Phosphonium,[(1E)-2-carboxyethenyl]triphenyl-, bromide (9CI) Structure](https://image.chemsrc.com/caspic/236/22038-50-2.png)
