Acid-catalyzed hydrolyses of bridged bi- and tricyclic compounds-XII: Kinetics of hydration of 2-norbornenone,a special β,γ-unsaturated ketone

The reaction rates, activation parameters, solvent deuterium isotope effects, and dependences of rates on acid concentration measured for the hydration of 2-norbornenone and its four Me-substituted homologs in aqueous acid agree with the slow protonation of the CC double bond (A-S_E2 mechanism). Thus the mechanism differs from that reported for the isomerization (to α,β-unsaturated ketones) of unbridged β,γ-unsaturated ketones, e.g. 3-cycloalkenones and Δ⁵-3-ketosteroids, under catalysis by acid.