nucleophilic aromatic substitution

chemical reaction

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July 1, 2026

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Nucleophilic aromatic substitution is a chemical reaction where a nucleophile, an atom or molecule seeking a positive center due to its available electron pair, attacks an aromatic ring. This type of reaction is not easily achieved unless the aromatic ring has electron-attracting substituents, such as a nitro group.12

The process typically involves two stages: the addition of the nucleophile, followed by the expulsion of a negatively charged group. Electron-withdrawing groups facilitate this reaction by stabilizing the intermediate negative charge. An example is the displacement of a fluoride ion from 2,4-dinitrofluorobenzene by a nucleophile like ethoxide ion.2

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organohalogen compound
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Nucleophilic aromatic substitution is a practical synthetic reaction only when the aryl halide bears a strongly electron-attracting substituent, such as a nitro group NO₂, at a position ortho or para to the halogen, as in 1-chloro-4-nitrobenzene:
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Nucleophilic aromatic substitution is a practical synthetic reaction only when the aryl halide bears a strongly electron-attracting substituent, such as a nitro group NO₂, at a position ortho or para to the halogen, as in 1-chloro-4-nitrobenzene:
Read More