Acid‐catalyzed hydrolysis of bridged bi‐ and tricyclic compounds. XXXVIII—Kinetics and mechanisms of 1‐ and 3‐nortricyclanols

The disappearance of 1‐ and 3‐nortricyclanols ( 1‐OH and 2‐OH ) in aqueous perchloric acid was followed by capillary GC at different temperatures and acid concentrations. 1‐OH is ca 1000 times more reactive than 2‐OH . The activation parameters, solvent deuterium isotope effects and parameters of excess acidity equations were measured and the products were studied. Both isomeric nortricyclanols react according to the Ad E 2 mechanism, i.e. the cyclopropane ring is protonated at the rate‐determining stage of the reaction. The protonation causes, in the case of 1‐OH , an isomerization called homoketonization with 2‐norbornanone as the only product and, in the case of 2‐OH , hydration, i.e. the formation of hydroxyl‐substituted norbornyl cations, the fast attack of which by water produces several norbornanediols. Copyright © 2001 John Wiley & Sons, Ltd.