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 opposite directions. 2. They show different properties in a chiral chemical environment.