Asymmetric synthesis as one of the most important areas of the synthetic chemistry, has
experienced a very fast development in the last three decades. After the pioneer works
of Pasteur, van Hoff and LeBel in the 19th century, chemists realized that some
chemical compounds can exist in two stereomeric forms due to a different spatial
arrangement of their atoms. From a stereochemical point of view, only molecules that
possess just an axis of symmetry, namely the ones that belong to the C1, Cn or Dn
symmetry groups, are of interest, since such molecules and their mirror images do not
coincide in space.
This phenomenon is called chirality. Chiral molecules that behave as
an object and a mirror object are known as enantiomers. If there are not any chiral
external influences, the enantiomers are physically and chemically identical. However,
they differ in two aspects:
1. They rotate the plane of the polarized light to the same degree in the
2. They show different properties in a chiral chemical environment.