Isotopic Labeling Study of the Ketonic Decarboxylation Mechanism

Ketonization mechanism via surface carboxylate enolization and formation of beta-ketoacid is supported by experiments with isotopic labels. Both cross-ketonization and H/D exchange of alpha protons demonstrate preferential enolization of the less substituted carboxylic acid. The enolization equilibrium controls concentration of the enolized species on surface and the global ketonization rate.