Bromination of p-cresol, 2-bromo-p-cresol, 3, 4-dimethylphenol, and mesitol in trifluoromethanesulfonic acid gives as the main product the bromo derivative with bromine meta to hydroxyl, a result attributed to the intermediate formation of a bromodienone and its rearrangement. Phenol does not give m-bromophenol in trifluoromethanesulfonic acid. 4- Bromo-2, 4, 6-trimethylcyclohexa-2, 5-dienone rearranges to 3-bromomesitol in ...