Lipase-Catalyzed Enantioselective Ring Opening of Unactivated Alicyclic-Fused β-Lactams in an Organic Solvent

A highly efficient and very simple method was developed for the synthesis of enantiopure β-amino acids (e.g. cispentacin) and β-lactams through the enzyme-catalyzed enantioselective ring opening of unactivated alicyclic β-lactams in organic media. High enantioselectivity (E > 200) was observed when the Lipolase (lipase B from Candida antarctica)-catalyzed reactions were performed with H₂O (1 equiv) in diisopropyl ether at 60 °C. The resolved products, obtained in good chemical yield (36−47%), could be easily separated.