N.m.r. study of reversible hydration of aliphatic aldehydes and ketones. Part 4.—Isotopic oxygen exchange of cycloalkanones

Rates of oxygen exchange of cyclobutanone, cyclopentanone, cyclohexanone, and cycloheptanone in aqueous solutions were studied. Rate constants for acid and base catalyses were derived. The rate constants for base catalysis follow the trend of reactivity expected from the I-strain theory. However, in acid catalysis this order was not obeyed. The effect of the basicity of the carbonyl group on the acid-catalyzed rate constant is discussed; the “anomaly” observed in acid catalysis is due to the extremely low basicity of cyclobutanone.