Chiral Separations. Chiral Dynamic Chromatography in the Study of Stereolabile Compounds

Chromatography on chiral stationary phases has been recently used as an additional tool for the study of internal molecular dynamics of a range of stereochemically labile organic compounds and for the determination of kinetic parameters of the reversible isomerization of one enantiomer into the other occurring during chromatography [enantio- and diastereoselective dynamic chromatography (DC)]. Within this context, the implementation of highly efficient chromatographic techniques pushed to their extreme limits represents a very effective method to extract thermodynamic and kinetic data, otherwise difficult or impossible to obtain by classical alternative approaches, such as dynamic nuclear magnetic resonance spectroscopy or batchwise thermal equilibration studies. This chapter provides a basic overview of the concepts behind the determination of stereoisomerization rate constants and activation barriers by DC. Several examples of the application of such technique in the study of model stereochemically labile compounds have been provided, with a focus on the extreme conditions of temperature and speed of analysis that can be achieved using state-of-the-art materials, columns, and instrumentation.