Acid-Catalyzed Hydrolysis of Bridged Bi- and Tricyclic Compounds. XXXIII. Hydration of exo- and endo-5-Methoxy-2-norbornenes and 3-Methoxynortricyclane.

Kinetics and mechanism of acid-catalyzed hydration of 5-hydroxymethyl- and 5-phenoxymethylnorborn-2-enes †

“…It is possible to estimate the Ad E 2 hydration rate constants for substrates 3-6 on the basis of the values measured for several exo-and endo-5-X-substituted norborn-2-enes. 14, 15 The logarithms of the rate constants, as extrapolated to 1.00 M HClO 4 at 298 K, obey fairly (Fig. 1) the substituent constants σ I q .…”

“…log (k o /M Ϫ1 s Ϫ1 ) vs. T Ϫ1 is linear (r = Ϫ0.999 98 and Ϫ0.9996, respectively) giving the following activation parameters: ∆S ‡ = ϩ14 ± 5 and ϩ16 ± 4 J K Ϫ1 mol Ϫ1 and ∆H ‡ = 109.1 ± 1.6 and 110.2 ± 1.2 kJ mol Ϫ1 , respectively, at 298 K. The parameters are in agreement with the increasing trend of the entropy and enthalpy of activation with decreasing acid concentration (see above), whereas the positive entropies of activation are less typical of the Ad E 2 mechanism. 12,14, 15 If eqn. ( 3) is reverted back to the linear form [eqn.…”

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

“…The retention times and spectra were also compared with those recorded for six methoxynorborneols formed in the hydration of 3-methoxynortricyclane (2-OMe). 21 The approximate amounts of the Table 2 considered isomeric norbornanediols are shown in Scheme 2. Accordingly, the C-1-C-6 edge of the cyclopropane ring opposite to the 3-substituent is cleaved most easily, producing mainly 2,7-norbornanediols (4 and 5), in agreement with earlier observations.…”

“…Accordingly, the C-1-C-6 edge of the cyclopropane ring opposite to the 3-substituent is cleaved most easily, producing mainly 2,7-norbornanediols (4 and 5), in agreement with earlier observations. 6,[21][22][23]…”

Acid-catalyzed hydrolysis of bridged bi- and tricyclic compounds. XXXVII. Kinetics and mechanisms of 1- and 3-acetoxynortricyclanes

“…It is also possible to check the correctness of the rate constant k É (Ad E 2) for 1, because the corresponding values have been measured for several 3-X-substituted notricyclanes in HClO 4 (aq.). 5,11,[21][22][23][24][25] They are presented, as extrapolated to an acid concentration of 1.00 mol dm À3 and a temperature of 298.2 K, as a function of the substituent constant ' q I 26 of X in Fig. 3.…”