title: Fomenting proton anisochronicity in the CH2D group.
abstract: A novel C-D...N interaction promotes an equilibrium isotope effect that causes a large chemical shift difference (43 ppb, 22 degrees C) for the diastereotopic methyl protons in the (N-CH2D)-(-)-isosparteinium cation. The observed chemical shift difference is in surprising agreement with a prediction of 44 ppb based upon an ab initio protocol. These calculations are also shown to reproduce the experimental shift difference in Anet's alpha-deutero-1,2-dimethylpiperidine (theory, 17 ppb; experiment, 14 ppb). The isosparteine-derived system described herein may provide an improved method for assigning the configuration and enantiomeric purity of stereogenic methyl groups (R-CHDT) by tritium NMR spectroscopy.
authors.affiliation: Department of Chemistry, Pomona College, 645 North College Avenue, Claremont, CA 91711-6338, USA.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Allen
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: O'Leary