ABSTRACT
There are two ways of obtaining chiral substances using a chiral crystal environment. One is to produce the chiral compounds from the prochiral ones, and the other is to obtain the chiral compounds from racemic ones. The mechanism of the racemic-to-chiral transformation and inversion processes are examined, it may be better to explain the solid-state photoreaction with retention of the single crystal form, which is called a crystalline-state reaction. Both of the racemic crystals of the piperidine and pyrrolidine complexes have chiral space groups before irradiation. The most important requirement for the racemic-to-chiral transformation is that the two molecules with R and S configurations crystallize in a chiral space group. Molecules should be most closely packed in a crystal from the thermodynamical point of view. If, however, a molecule, has chiral groups or moieties, some void space will appear in the crystalline lattice.
