Uniquely isomeric

A novel approach to determining enantiomeric excesses in pharmaceutical reaction schemes based on NMR has been developed by French chemists. The researchers exploit the intramolecular dynamic processes of bi-aryl derivatives of compounds of interest using deuterium NMR. The weak ordering revealed by a polypeptide chiral liquid crystal solvent can be used to calculate activation energies for the conformational exchanges. Philippe Lesot and colleagues at the Université de Paris-Sud envisage using a series of chiral atropisomers to determine the effect of the position and size of substituent on the internal rotation barrier of small molecules.