Acid-catalyzed hydrolysis of bridged bi- and tricyclic compounds. XXXVI. Kinetics of exo- and endo-2-methoxynorbornanes

The disappearance of exo- and endo-2-methoxynorbornanes in aqueous perchlor ic acid was followed by capillary GC at different temperatures and acid con centrations. The high exo/endo rate ratio (8850 at 308 K in 7.0 M HClO4), t he positive entropies of activation, the parameters of the excess acidity e quation and the products are in agreement with the hydrolysis by the A-1 me chanism. The ether oxygen of the exo-epimer is much more basic than that of the endo-epimer (Delta pK(a)approximate to 2) according to the excess acid ity equations derived for both slightly and highly protonated substrates.