Lipase-catalysed resolution of γ- and δ-lactones
Lipase-catalysed stereoselective hydrolysis of a family of saturated γ- and δ-lactones was investigated. Increasing the chain length from δ-octalactone to δ-dodecalactone leads to higher enantiomeric excess. Best results were found using a lipase from Pseudomonas species (KW51) yielding highest enantiomeric excesses (greater than 99%ee at 50% conversion, E>100) at short reaction times (10 h) for δ-undecalactone and δ-dodecalactone. In contrast, γ-lactones were resolved less efficiently. Highest enantioselectivities (70%ee at 50% conversion, E=11) were found for γ-nonalactone. Optimum reaction conditions were found at pH 8 and 12.5°C.