Isotope effects in nucleophilic substitution reactions. V. The mechanism of the decomposition of 1-phenylethyldimethylphenylammonium halides in chloroform

Article abstract of DOI:10.1139/v86-200

Secondary α and β hydrogen-deuterium kinetic isotope effects have been used together to show that the S_N reaction between 1-phenylethyldimethylammonium ion and bromide or iodide in chloroform occurs by way of an S_N2 mechanism within a triple ion in spite of the fact that it reacts faster than the primary substrate, benzyldimethylphenylammonium bromide.The very loose transition state and steric effects in the ground state appear to be responsible for the unusually fast S_N2 reactions between 1-phenylethyldimethylphenylammonium ion and halide ions in chloroform.