Chapter 24: Phenols

Electrophilic Aromatic Substitution Reactions of Phenols

Summary

• Phenols are potentially very reactive towards electrophilic aromatic substitution.
• This is because the hydroxy group, -OH,  is a strongly activating, ortho- / para- directing substituent (review)
• Substitution typically occurs para to the hydroxyl group unless the para position is blocked, then ortho substitution occurs.
• The strong activation often means that milder reaction conditions than those used for benzene itself can be used (see table below for a comparison)
• Phenols are so activated that polysubstitution can be a problem  (similar problems occur with anilines)

• Electrophilic Aromatic Substitutions reactions of Benzenes
• Electrophilic Aromatic Substitutions reactions of Aryl Ethers
• Electrophilic Aromatic Substitutions reactions of Aryl Amines

© Dr. Ian Hunt, Department of Chemistry