Enzyme Catalysts and Chirality

I denotes group in the plane of the paper denotes group oriented toward viewer denotes group oriented away from viewer 

FIGURE 14.13 Illustration of the chiral herbicide mecoprop only the R enantiomer has herbicidal activity and is now marketed in the enantiomeric pure form. 

Normally, when a chiral compound is synthesized by conventional chemical means, a racanic mixture of the two enantiomers is produced. Because of their essentially identical chemical properties, they are very hard to separate. However, it is possible to produce enantiomerically pure chemical compounds with appropriate enzymatic catalysts. Furthermore, it is possible to use enzymatic catalysts to convert racemic mixtures of compounds to enantiomerically pure forms. In one of the larger such industrial operations, the German chmical firm BASF now uses enzymatically catalyzed processes to prepare enantiomerically pure amines in thousand-ton quantities. 

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