Medium effects. II. Cyclization of 6-heptenyl p-nitrobenzenesulfonate during solvolysis in 2,2,2-trifluoroethanol

✍ Scribed by Walter S. Trahanovsky; Michael P. Doyle

• Publisher: Elsevier Science
• Year: 1968
• Tongue: French
• Weight: 205 KB
• Volume: 9
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)89709-9

✦ Synopsis

Solvolysis of 5-hexenyl arenesulfonates can be viewed as two competing nucleophilic reactions: a) external nucleophilic attack by the hydroxylic solvent to give 5-hexenyl products and b) internal nucleophilic attack by the olefin to give cyclic products (1). It is possible that the ratio of open to cyclic products may be a measure of the relative solvent nucleophilicity of a solvent mixture towards attack on alkyl arenesulfonates or halides. In order for t! his ratio of open to cyclic products to be a measure of solvent nucleophilicity, ground state changes must be more important than transition state changes (1). Our initial study of the solvolysis of 5-hexenyl E-nitrobenzenesulfonate in various solvent mixtures composed of 20% acetic acid and 80% nonhydroxylic solvent in the presence of urea showed that transition state changes may or may not be as important as ground state changes and thus the ratio of open to cyclic products may or may not measure solvent nucleophilicity (1).

Additional studies should eventually show whether or not this ratio is a good measure of solvent nucleophilicity. In this communication, we wish to report that if we assume that this ratio does measure solvent nucleophilicity, then