ABSTRACT
Despite the large number of elaborate enantioselective syntheses for the preparation of a single enantiomer to achieve industrial and scientific goals, the separation and purification of enantiomers (components of racemic compounds) is also necessary. Hence, we present the most often used thought-provoking modern methods based on momentous recognitions (e.g. spontaneous resolution, induced crystallization, resolution by formation of diastereomers, resolution by formation of non-covalent diastereomers, resolution by diastereomeric salt formation, resolution by diastereomeric complex formation, "half equivalent" methods of resolution, separation by crystallization, separation by distillation, separation by supercritical fluid extraction, resolution with mixtures of resolving agents, resolution with a derivative of the target compound, enantioselective chromatography, resolution by formation of covalent diastereomers, resolution by substrate selective reaction, kinetic resolution without enzymes, kinetic resolution by enzyme catalysis, hydrolytic and redox enzymes, kinetic and thermodynamic control, resolutions combined with 2nd order asymmetric transformations, enrichment of partially resolved mixtures, role of the solvent and methods of optimization in the separation of diastereoisomers, non-linear effects and selected examples of resolution on an industrial scale).
ABSTRACT
Structures of chiral and achiral alcohol-O,O'-dibenzoyl-(2R,3R)-tartaric acid (DBTA) complexes were investigated by single-crystal X-ray diffraction (seven new crystal structures were determined). The complexes contain DBTA and chiral alcohol in 1:1, DBTA and achiral alcohol in 1:2 host-guest stoichiometry. The hydrogen bonding structures of chiral alcohol-DBTA and achiral alcohol-DBTA complexes are different, but within a subclass they are isostructural ones.
