Ionic liquids as additives in the pig liver esterase (PLE) catalysed synthesis of chiral disubstituted malonates

This report describes the first application of hydroxylated and epoxylated ionic liquids as additives in the enantioselective hydrolysis of prochiral diester malonates using pig liver esterase (PLE) as catalyst. Less than 1% of a hydrophilic functionalised ionic liquid, used in combination with 10% isopropanol/water is sufficient to enhance the activity of the enzyme by a factor of up to 4 and also to increase the enantioselectivity of the reaction. Immobilisation of the PLE on Eupergit® C enabled successful recycling of the enzyme system.