Chiral Deuterium Labeling: New Method for Determination of Rotational Propensities

Article abstract of DOI:10.1021/ja00354a030

Determination of internal rotational propensities in thermal rearrangements of cyclic compounds has, in the past, involved the use of optical activity as a tracer and has required usually arduous correlation of configurations between the educt and products by chemical means.Replacement of this method by introduction of a chiral, diastereomeric deuterium hydrogen methylene group permits configurational relations to be established by NMR - either 2H NMR or 1H NMR alone or with LIS enhancement.As a first application of the new method, the relative rotational propensity, R_A, of the cyano and isobutenyl groups in 1-cyano-2-isobutenyl-2,3-dideuteriocyclopropane has been determined to be 3.9 +/- 0.5.