Nucleophilic Substitution in Vinylic Halides

Abstract

NUCLEOPHILIC substitution of a halogen atom directly attached to a double bond, as in the vinyl and phenyl halides, does not readily take place^1–3. Nevertheless, cases of substitution in vinylic halides are recorded in the literature⁴, and facile substitution has been reported for compounds containing electron-withdrawing substituents in the β-position with respect to the halogen⁵. An obvious analogy exists with aromatic systems in which, as has been demonstrated by numerous experiments, nucleophilic substitution occurs readily only when electron-withdrawing groups are present at suitable positions in the ring.