ACID-CATALYZED HYDROLYSIS OF BRIDGED BICYCLIC AND TRICYCLIC COMPOUNDS .32. 7-OXA-2-OXOBICYCLO[2.2.1]HEPTANE - KINETICS, PRODUCTS AND MECHANISM

7-Oxa-2-oxobicyclo[2.2.1]heptane (7-oxa-2-norbornanone) produces in concentrated (7 mol dm-3) aqueous perchloric acid ca. 31% phenol and several other products, which are mostly substituted phenols. The activation entropy, the solvent deuterium isotope effect and the slope parameters (m(not-equal)) of the linear excess acidity plots support tie bimolecular mechanism (A-2) for the hydrolysis, but the products are evidently formed via the 3-oxo-4-hydroxy-1-cyclohexyl cation, which is typical of the unimolecular mechanism (A-1). Thus the reaction probably takes place by the A-2 (carbocation) mechanism. The data are compared with those recently measured for 7-oxabicyclo[2.2.1]heptane and 7-oxa-5-oxo-2-bicyclo[2.2.1]heptane.