Studies on the Molecular Geometry of the Norbornyl Cation. I. Synthesis and Acetolysis of the exo- and endo-4,5-exo-Trimethylene-2-Norbornyl P-Toluenesulfonates

E. J. Corey, Richard S. Glass

Research output: Contribution to journalArticle

64 Scopus citations

Abstract

4,5-exo-Trimethylene-2-norbornene (10) has been synthesized from a monosubstituted cyclopentadiene 9 using an intramolecular Diels-Alder reaction, and from this intermediate exo- and endo-4,5-exo-trimethylene-2-norbornyl p-toluenesulfonates (11, R = Ts, and 16, R = Ts) have been prepared. These sulfonates undergo acetolysis (25°) at relative rates of 8.6:1. The ratio of rate constants (25°) for acetolysis of the exo-sulfonate 11, R = Ts, and 2-exo-norbornyl p-toluenesulfonate is 1:85, where as the corresponding ratio for the endo-sulfonate 16, R = Ts, and 2-endo-norbornyl p-toluenesulfonate is 1:2.5. The depressed rate for the tricyclic exo-sulfonate 11, R = Ts, relative to 2-exo-norbornyl p-toluenesulfonate is readily explained in terms of bridging of carbon in the transition state for ionization, but seems to be contrary to expectations based on ionization to a localized (classical) carbonium ion. Thus, the present results favor the bridged-ion mechanism for acetolysis of 2-exo-norbornyl arenesulfonates.

Original languageEnglish (US)
Pages (from-to)2600-2610
Number of pages11
JournalJournal of the American Chemical Society
Volume89
Issue number11
DOIs
StatePublished - May 1 1967

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Fingerprint Dive into the research topics of 'Studies on the Molecular Geometry of the Norbornyl Cation. I. Synthesis and Acetolysis of the exo- and endo-4,5-exo-Trimethylene-2-Norbornyl P-Toluenesulfonates'. Together they form a unique fingerprint.

  • Cite this