ABSTRACT
Enantiomers have identical chemical properties except when reacting with other chiral species or with achiral species in the presence of chiral additives. Conversely, any molecule that is superimposable on its mirror image is achiral. The presence of a stereocentre is not a requirement for a molecule to exhibit chirality, it is simply the most common cause of chirality. The d,l-nomenclature system is still widely used for amino acids and carbohydrates, but has been superseded for other classes of compounds. To determine whether a chiral species belongs to the d or the l-series, it is drawn as a Fischer projection with the first atom of the longest carbon chain at the top. Many natural products which contain a stereocentre exist in nature as a single enantiomer. This is particularly important for amino acids and carbohydrates, since all common, naturally occurring, chiral amino acids have the l-configuration, and all common, naturally occurring carbohydrates have the D-configuration.
