Correlation analysis of the rates of solvolysis of 4-bromopiperidine: a reaction following a Grob fragmentation pathway

Eur J Chem. 2017 Jun;8(2):162-167. doi: 10.5155/eurjchem.8.2.162-167.1566. Epub 2017 Jun 30.

Abstract

A Grunwald-Winstein treatment of the specific rates of solvolysis of 4-bromopiperidine gives for aqueous ethanol, methanol, acetone, and dioxane a very good logarithmic correlation against the YBr solvent ionizing power values with a slope (m value) of 0.46±0.02, consistent with the operation of a synchronous Grob fragmentation mechanism. When the organic component of the solvent is 2,2,2-trifluoroethanol (TFE), the data points show a negative deviation, consistent with an appreciable deactivating interaction of the acidic TFE component of the solvent with the lone-pair of electrons present on the nitrogen.

Keywords: 4-Bromopiperidine; Correlation; Grob fragmentation; Grunwald-Winstein equation; Mechanism; Solvolysis.