Unequal primary kinetic isotope effects in the base-catalysed H–D exchange of diastereotopic protons

1 January 1980

journal article
Published by Canadian Science Publishing in Canadian Journal of Chemistry

Vol. 58 (1) , 72-78
https://doi.org/10.1139/v80-012

Abstract

Primary kinetic isotope effects have been measured for the base-catalyzed exchange reaction of 4′,1″-dimethyl-1,2,3,4-dibenzcyclohepta-1,3-diene-6-one, 1. It was found that the isotope effects k^H/k^T and k^D/k^T for the faster exchanging protons (13.6 and 3.8 respectively) are significantly larger than the corresponding values for the slower exchanging protons (4.6 and 1.6 respectively). These differences could result from truly unequal isotope effects due to transition state differences or intrusion of a second pathway for exchange of the less reactive proton in the dedeuteration reaction. The data appear to support the latter interpretation. The secondary deuterium isotope effect was found to be 1.18.

Keywords

This publication has 0 references indexed in Scilit: