Candida antarctica lipase B catalysed kinetic resolutions: Substrate structure requirements for the preparation of enantiomerically enriched secondary alcanols

Abstract

The lipase B of the Candida antarctica yeast displays high enantioselectivity in transesterification reactions with chiral secondary alcohols in non-aqueous media. This was exploited to resolve a series of racemates structurally related to 2-octanol, namely 3-hydroxy-1-undecyne, 3-hydroxy-1-nonene, 3-nonanol, 1-chloro-2-octanol, 2-methyl-3-nonanol, 2,2-dimethyl-3-nonanol. The substrates were designed to probe the alcohol binding part of the active site of the lipase. The first four racemates could be resolved to produce compounds of high enantiomeric purity. A lipase catalysed transesterification of 1-chloro-2-octanol was observed. 2-Methyl-3-nonanol and 2,2-dimethyl-3-nonanol did not form any detectable amounts of product ester. The kinetic resolutions of the alcohols were performed with S-ethyl thiooctanoate as the acyl donor.