32.2.6—Phenol directing effects

In phenol, the –OH group is an activating, 2/4-directing substituent. Electrophiles therefore enter mainly at the two ortho positions (2 and 6) and the para position (4).

The two ortho positions are equivalent in an unsubstituted ring, so products are often described as 2-, 4- or 2,4,6-substituted phenols.

Bromination of phenol gives 2,4,6-tribromophenol because all three favoured positions are available and the ring is strongly activated.

The rule predicts preferred positions, not that every phenol reaction must give all three products; reagent amount and steric effects still matter.