CHEM 130 Lecture Notes - Lecture 4: Tris, Acyl Chloride, Pseudomonas Fluorescens
Document Summary
As noted earlier, the different physical properties of diastereomers renders them more easily separated than enantiomers. Thus, reaction of a racemate with an enantiomerically pure chiral reagent gives a mixture of diastereomers, which can then be separated. Reversing the first reaction then leads to the separated enantiomers plus the recovered reagent. Experience indicates that ionic salts are easily formed and crystallized. After separation of isomers, the acid & base components of the salt may be regenerated as separate compounds. An example is found in the resolution of ( )-tartaric acid by reaction with ( )cinchotoxine (structure below). The diastereomeric salts in the product mixture have such different water solubility that the ( ):(+) component precipitates while the (+): (+)-diastereomer remains in solution. Once the salts are separated, the base may be dissolved in dilute acid, leaving behind the enantiomers of tartaric acid.
