A computational study on the sources of deuterium secondary kinetic isotope effects in carbocation-forming reactions

Calculations at the HF-DFT hybrid Becke3LYP level of theory have been undertaken on protonated 2-exo- and 2-endo-norbornanols as model substrates for 2-exo- and 2-endo-norbornyl brosylates to explore the source of the experimentally determined deuterium secondary kinetic isotope effects (KIEs). Calculations on protonated alcohols as models reproduce the "normal" behaviour of 2-endo substrate 5. The observed endo γ-KIE in the 7-unsubstituted 2-exo system 4 is shown to arise from internal return, while those in the 7-chloro substituted 2-exo substrates 1 and 2 can be explained with competing 1,3 (6,2)-elimination.Key words: deuterium secondary kinetic isotope effects, 2-norbornyl cation, Becke3LYP.

A computational study on the sources of deuterium secondary kinetic isotope effects in carbocation-forming reactions Journal Articles