Deuterium NMR stereochemical analysis of threo-erythro isomers bearing remote stereogenic centres in racemic and non-racemic liquid crystalline solvents

We report the proton-decoupled deuterium NMR study of labelled diastereomer s with remote stereogenic carbons dissolved in various mixtures of poly-gam ma-benzyl-L-glutamate (PBLG) and poly-gamma-benzyl-D-glutamate (PBDG) liqui d crystalline solutions. The evolution of quadrupolar splitting as well as the diastereomeric and the enantiomeric discrimination versus the proportio n of PBLG and PBDG in the liquid crystalline phase is studied. It is shown that racemic liquid crystalline solutions of PBLG and PBDG may be used to m easure diastereomeric excess (de). Thereafter the spectrum in PBLG solution allows for measuring the enantiomeric excess (ee) of each diastereomer. Th ese first results suggest substantial prospects in the field of the analysi s of diastereomers with remote stereogenic carbons. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.