The log kexovs. log kendo correlation as a mechanistic criterion; on the mechanisms of solvolysis of norbornyl derivatives and base-catalyzed isotope exchange of norbornanones

Rate data for the acetolysis of exo-norbornyl-sulfonates have been correlated with those for the corresponding endo isomers. It is shown that the slopes of the log k exo vs. log k endo plots reflect the difference in delocalization between the transition states derived from the exo and endo isomers, respectively. The log k exo vs. log k endo plot, which is comprised of the parent norbornyl sufonate and its derivatives substituted at the 5, 6, and 7 positions, has a slope of 1.11 ± 0.08, which establishes that σ bridging is absent in the transition state obtained from the exo isomer. A similar analysis of base-catalyzed hydrogen–deuterium exchange rates of norbornanones reveals that exo proton exchange is more sensitive to substituent effects than the corresponding endo process.