Oxidation of Tyrosol Derivatives Using Polymer-Supported IBX

Significance

Efficient oxidative introduction of a hydroxyl group into tyrosol derivatives using polymer-supported IBX was described. Thus, the polymer-supported IBX 3 was prepared from 2-amino-5-hydroxybenzoic acid (1) and chloro­methylpolystyrene 2 according to the reported procedures (G. Sorg, A. Mengel, G. Jung, J. Rademann Angew. Chem. Int. Ed. 2001, 40, 4395). Oxidation of tyrosol derivatives 4 was ­carried out with the polymer-supported IBX 3 in dimethyl carbonate (DMC) to give hydroxytyrosol 5 in quantitative yield. The polymeric oxidizing agent 3 was recovered, regenerated, and reused four times without any loss of efficiency to give the hydroxytyrosol 5a in high yield.