The lipase-catalyzed kinetic resolution of (R/S)-3-phenylbutyric acid 2 using solid-supported cyclohexane-1,3-dione (CHD) 6 is described. In each case the predominant enantiomer observed, after cleavage from the resin, was (R)-(−)-3-phenylbutyric acid (R)-2 (ee > 99%) rather than the expected (S)-enantiomer of 2. This observation is in contrast to the fact that Chromobacterium viscosum lipase shows high enantiospecificity for the (S)-enantiomer in the corresponding solution-phase hydrolysis reactions. The (R)-acyl group was subsequently released from the resin by NaOH hydrolysis, and the yield of the reaction could be improved by triple acylation of the resin.
- lipase-catalyzed kinetic resolution
- capture and release strategy