Carbon Participation in the Solvolysis of 6-endo-substituted 2-exo-Norbornyl Toluenesulfonates. Norbornanes Part 6

Article abstract of DOI:10.1002/hlca.19810640736

The solvolysis rate constants k for the 6-endo-substituted 2-exo-norbornyl toluenesulfonates 7 have been determined.Values of logk correlate well with the respective inductive constants of the substituents except when the latter are nucleophilic and therefore lead to endo-cyclization, or when they are n-electron donors and cause concerted fragmentation.In general 6-endo-substituted tosylates 7 react somewhat more slowly than their 6-exo-epimers. Identical or different mixtures were obtained from the C(6)-epimers 7 and 1 depending on whether the substituent was an electron donor or acceptor.It is concluded that donor substituents at C(6) enhance 1,3-bridging in the intermediate epimeric cations and lead to their rapid and complete equilibration, and that electron acceptors reduce bridging and hence their equilibration rates.