Chiral Amines as Resolving Agents

Amines also form salts with organic acids. This reaction is used to resolve enantiomeric acids (Sec. 5.12). For example, (f )- and (S)-lactic acids can be resolved by reaction with a chiral amine such as (S)-l-phenylethylamine  

The salts are diastereomers, not enantiomers, and can be separated by ordinary methods, such as fractional crystallization. Once separated, each salt can be treated with a strong acid, such as HCl, to liberate one enantiomer of lactic acid. For example. 

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A Chiral Amines as Resolving Agents. Resolution of Racemic Acids... 

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