32.2.7—Reactions of phenolic compounds

A phenolic compound has an –OH group directly attached to an aromatic ring. Its reactions can be predicted by combining phenol’s two features: an acidic O–H proton and an activated, 2/4-directing ring.

Other substituents on the ring can alter the rate, acidity and available positions, so transfer the pattern only after checking their electronic effects and steric crowding.

Naphthol can form a phenoxide with base and undergo electrophilic substitution at positions made electron-rich by the hydroxyl group, but the fused ring geometry changes which sites are available.

Do not treat every aromatic –OH compound as identical to phenol; ring fusion and additional substituents can change regioselectivity.