Lipase-catalyzed Transesterification in organic Solvents: Preparation and Enantiodifferentiation of optically enriched 4(5)-alkylated 1,4(1,5)-olides

Article abstract of DOI:10.1016/S0957-4166(00)82013-3

Porcine pancreatic lipase (PPL) catalyzed intramolecular transesterification of n-propyl esters of 4(5)-hydroxyalkanoic acids (C5-C12) in diethyl ether (20 deg C) yielded (S)-4-alkylated 1,4-olides of high optical purity (ee > 80percent) and optically pure (R)-4-hydroxyalkanoic-n-propylesters, but exhibited low enantioselectivity for (S)-5-alkylated 1,5-olides (ee=10-20percent).The chiral analysis of 4(5)-hydroxyalkanoic esters was performed by HRGC and HPLC after their derivatization with (R)-(+)-1-phenylethylisocyanate, (S)-O-acetyllactic acid chloride, and (R)-(+)-α-methoxy-α-trifluoromethylphenylacetic acid chloride.The enantiodifferentiation of 1,4(1,5)-olides was achieved by HPLC on a chiral (ChiraSpher) using an on-line optical rotation detector (ChiraMonitor).