The title compounds serve as potential precursors to aryloxenium ions, often proposed, but primarily uncharacterized intermediates in phenol oxidations. The uncatalyzed and acid- catalyzed decomposition of 4-acetoxy-4-phenyl-2, 5-cyclohexadienone, 2a, generates the quinol, 3a. 18O-Labeling studies performed in 18O-H2O, and monitored by LC/MS and 13C NMR spectroscopy that can detect 18O-induced chemical shifts on 13C resonances, show ...
