Nucleophile-solvent isotope effects between methanol isotopomers during the interception of aziridinium imide-‘like’ closed intermediates

Deuterated methanol isotopomers were found to compete efficiently with normal methanol during the interception of an intermediate with structural characteristics of the aziridinium imide, formed in the reaction of N-phenyltriazolinedione with simple alkenes such as 2-methylpropene, 2-methyl-2-butene, and 2,3-dimethyl-2-butene. In general, a (trideuterio)methyl-group bearing methanol was found to add at the tertiary carbon atom of the intermediate more efficiently with regard to hydrogen isotopomeric methanol, and this result is explained in terms of the nucleophile-solvent isotope effect in an S_N2-‘like’ transition state of solvent addition to the intermediate.