Phenol oxidation with hypervalent iodine reagents
Phenol oxidation with hypervalent iodine reagents leads to the formation of quinone-type products or iodonium ylides, depending on the structure of the phenol. Trapping of either product is possible with a suitable reagent, and this method is often employed with a second process.
Source: Wikipedia — Phenol oxidation with hypervalent iodine reagents (CC BY-SA 4.0)