A New Route to Enantiopure β‐Aryl‐Substituted β‐Amino Acids and 4‐Aryl‐Substituted β‐Lactams through Lipase‐Catalyzed Enantioselective Ring Cleavage of β‐Lactams

Abstract

Abstract A simple and efficient direct enzymatic method was developed for the synthesis of 4‐aryl‐substituted β‐lactams and the corresponding β‐amino acid enantiomers through the CAL‐B (lipase B from Candida antarctica )‐catalyzed enantioselective ( E >200) ring cleavage of the corresponding racemic β‐lactams with 1 equiv. of H 2 O in i‐ Pr 2 O at 60 °C. The product ( R )‐β‐amino acids (ee≥98%, yields≥42%) and unreacted ( S )‐β‐lactams (ee≥95%, yields≥41%) could be easily separated. The ring opening of enantiomeric β‐lactams with 18% HCl afforded the corresponding enantiopure β‐amino acid hydrochlorides (ee≥99%).