Asymmetric Synthesis of Optically Active 3-Substitute< δ-Valerolactones Using Lipase in Organic Solvents

Abstract

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 δ-valerolactones were synthesized from the mono esters in overall yields of 34-62%. The -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.