Illustrated Glossary of Organic Chemistry

Directing group (director): In electrophilic aromatic substitution, a benzene ring substituent that influences benzene ring nucleophilicity and arenium ion stability, causing the incoming electrophile to favor attack at particular positions on the benzene ring.




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Ortho isomer
Minor product

Meta isomer
Major product

Para isomer
Minor product
Bromination of nitrobenzene via electrophilic aromatic substitution gives mostly the meta product, so the NO2 group is a meta director.