ASYMMETRIC-SYNTHESIS OF OPTICALLY-ACTIVE 3-SUBSTITUTED DELTA-VALEROLACTONES USING LIPASE IN ORGANIC-SOLVENTS

In organic solvents, lipase Amano P catalyzed the asymmetric ring opening of glutaric anhydrides bearing-CH2Cl,-CH2F and -OCH3 groups at position 3 with methanol and 1-butanol to afford the corresponding mono esters in 70-86% e.e. Optically active sigma-valerolactones were synthesized from the mono esters in overall yields of 34-62%. The R-configuration was assigned to the mono esters and the lactones by means of a CD analysis and chemical correlation. This indicates that the lipase preferentially attacked the pro-R carbonyl group of these anhydrides carrying hetero atoms, in keeping with the trend observed for glutaric anhydrides having simple alkyl substituents.