Key Concepts—Electrophilic Aromatic Substitution

Three Rules Describing the Reactivity and Directing Effects of Common Substituents (18.7-18.9) 

Summary of Substituent Effects in Electrophilic Aromatic Substitution (18.6-18.9) 

Inductive effect Resonance effect Reactivity Direc ting effect 

Polyhalogenafion occurs on benzene rings substituted by OH and NH2 (and related substituents) (18.10A). 

Vinyl halides and aryl halides are unreactive. The reaction does not occur on benzene rings substituted by meta deactivating groups or NHg groups (18.1 OB). 

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