Ionic liquids: efficient additives for Candida rugosa lipase-catalysed enantioselective hydrolysis of butyl 2-(4-chlorophenoxy)propionate

The Candida rugosa lipase-catalysed enantioselective hydrolysis of butyl 2-(4-chlorophenoxy)propionate 1 has been carried out in aqueous buffer with ionic liquid as co-solvent. The influence of ionic liquid on the catalytic efficiency and selectivity has been studied, using both hydrophobic and hydrophilic ionic liquids. The markedly enhanced enantioselectivity towards the R enantiomer of substrate 1 is observed under optimum additive conditions (1:1 composition of ionic liquid and buffer). Hydrophobic ionic liquids offered almost quantitative conversions with ee ≥ 99%.