91Ó°ÊÓ

Aryl halides comprising electron-withdrawing substituents undergo nucleophilic substitution reaction.The first step in this reaction is the nucleophilic addition of hydroxide ion to the aromatic ring resulting in a stabilized carbanion intermediate. The elimination of halide ion further leads to a substitution product.

The base KOH picks up the acidic proton of the phenol to generate a phenoxide ion. The nucleophilic attack of the phenoxide ion on the aryl fluoride generates a negatively charged Meisenheimer complex. The attack of this ion is facilitated by the electron-withdrawing nitro group present in the aryl fluoride. The fluoride ion gets eliminates to produce oxyfluorofen as the product.

Mechanism for the preparation of oxyfluorfen