Synthesis and NMR spectra of ¹⁷oxygen enriched phenols

An efficient and convenient method of preparing 17 O enriched phenols is described. Aryl boronic acids are oxidized with 17 O enriched potassium hydroperoxide. The 17 O labeled potassium hydroperoxide is prepared from the autoxidation reaction of benzhydrol with 17 O 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 % 17 O 2 starting material). 17 O 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 unenriched samples.