Chiral resolution
The use of chiral resolution to obtain enantiomerically pure compounds has the disadvantage of necessarily discarding at least half of the starting racemic mixture.The method was introduced (again) by Louis Pasteur in 1853 by resolving racemic tartaric acid with optically active (+)-cinchotoxine.One modern-day method of chiral resolution is used in the organic synthesis of the drug duloxetine:[4] In one of its steps the racemic alcohol 1 is dissolved in a mixture of toluene and methanol to which solution is added optically active (S)-mandelic acid 3.In the meanwhile the (R)-alcohol remains in solution unaffected and is recycled back to the racemic mixture by epimerization with hydrochloric acid in toluene.[9] This phenomenon allowed Louis Pasteur to separate left-handed and right-handed sodium ammonium tartrate crystals.
stereochemistryracemicenantiomersoptically activechiralAsymmetric synthesisdiastereomericchiral derivatizing agentsracemizedcarboxylic acidtartaric acidbrucineLouis Pasteurorganic synthesisduloxetinealcoholtoluenemethanolmandelic acidsodium hydroxideepimerizationhydrochloric acidChiral derivatizing agentAntimony potassium tartrateCamphorsulfonic acid1-Phenylethylaminechiral poolracematesenantiopuresodium ammonium tartrateoptical activityseedingsupersaturatedmethadonepetroleum etherethanolchiral column chromatographySheldonMarch, JerryPure Appl. Chem.Org. Process Res. Dev.J. Am. Chem. Soc.enantioselective synthesisChiralityStereocenterPlanar chiralityC2-symmetric ligandsAxial chiralitySupramolecular chiralityInherent chiralityStereoisomerEnantiomerDiastereomerMeso compoundRacemic mixtureEnantiomeric excessDiastereomeric excessOptical rotationNMR spectroscopy of stereoisomersUltraviolet–visible spectroscopy of stereoisomersRecrystallizationKinetic resolutionDiastereomeric recrystallizationAsymmetric inductionChiral pool synthesisChiral auxiliariesAsymmetric catalysisOrganocatalysisBiocatalysis