Chromatography-Free Enzymatic Kinetic Resolution of Secondary Alcohols

Racemic secondary alcohols were resolved by enzymatic esterification using Candida antarctica lipase B (CAL B). After derivatization of the unreacted enantiomer with phthalic anhydride, the resulting phthalic acid monoesters could be easily separated from the corresponding acetates by precipitation and filtration or distillation, thus avoiding laborious column chromatography, which is a major obstacle for large-scale reactions. This method has been successfully applied to the multigram synthesis of enantiopure pyridyl alcohols.