Contemporary chiral resolutions

15

INTRODUCTION
As most molecules in biology are chiral, the handedness of chiral drugs is often very important. Where one enantiomer can be a potent drug with little side-effects, the other enantiomer can be toxic. Therefore, the separation of enantiomers from a racemic mixture remains a topic of interest. Already in 1848, the French scientist Louis Pasteur performed the first resolution via crystal picking of a conglomerate forming phase of a tartaric acid salt. A few years later he performed the first resolution via diastereomeric salt formation, later coined as a classical resolution (1).
Since Pasteur’s discovery, the development of resolution approaches has not ground to a halt but inspired a large influx of ideas; from Pope-Peachey (2) to Dutch Resolution (3) and from preferential crystallization (4) to Viedma Ripening (5).
In this paper some practical examples are shown together with a less-known enantiomer self-disproportionation technique based on density differences (6).