ABSTRACT
This chapter discusses the stereochemical consequences of various reactions. Although many of these reactions create new stereocentres, if the starting material is achiral or racemic then the product of the reactions must also be achiral or racemic. In view of the limitations of preparing enantiomerically pure compounds either by resolution or using naturally occurring, enantiomerically pure starting materials, it would be very useful to have available methodology to convert achiral starting materials into chiral, non-racemic products. The carbonyl carbon of acetophenone is a prochiral centre, and the molecule has enantiotopic re- and si-faces. Enzyme catalysed asymmetric synthesis has all of the advantages and disadvantages of asymmetric synthesis using synthetic chiral catalysts. The same type of desymmetrization of a meso compound has also been achieved using chiral reagents, and synthetic chiral catalysts.
