AbstractAn efficient and convenient method of preparing17O enriched phenols is described. Aryl boronic acids are oxidized with17O enriched potassium hydroperoxide. The17O labeled potassium hydroperoxide is prepared from the autoxidation reaction of benzhydrol with17O enriched oxygen gas in the presence of potassium t‐butoxide. [0–17]Phenol, p‐bromo[0–17]phenol and p‐methoxy[0–17]phenol were prepared in good to modest overall chemical yields (40–60%) and high isotopic retention (82–90% from 16.8 atom %17O2starting material).17O NMR spectra of the three enriched phenols demonstrate the benefits of using enriched samples in reducing the total experiment time and greatly improving the signal‐to‐noise ratio compared to