The Effect of Ring Size on Reactivity: The Diagnostic Value of ‘Rate Profiles’

✍ Scribed by Eric Masson; Frédéric Leroux

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: German
• Weight: 288 KB
• Volume: 88
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200590110

✦ Synopsis

Abstract

The rates of cycloalkyl phenyl sulfide formation of a series of homologous bromocycloalkanes upon treatment with sodium benzenethiolate have been determined to ascertain the effect of ring size on reactivity. The ‘rate profile’, i.e., reaction rate vs. ring size, for these nucleophilic substitutions (S~N~2) was determined. A linear free‐energy relationship could be derived from computed hydride affinities of cycloalkanes and rates of typical S~N~1 reactions, whereas rates of S~N~2 reactions exhibited a strong discrepancy from the seven‐ up to the twelve‐membered rings. This discrepancy was rationalized by a careful examination of the geometry of the intermediates and transition states involved in these reactions.