Chemoenzymatic synthesis of enantiopure 1-phenyl-2-haloethanols and their esters

Several secondary haloalcohols have been resolved by esterification catalyzed by lipases A and B from Candida antarctica (CALA and CALB, respectively). Immobilized CALB (Novozym 435) gave better selectivities and faster reaction rates than CALA (Novozyme 735) with all of the substrates. Vinyl butanoate was the favoured acyl donor compared to vinyl acetate due to remarkably faster reactions. The alcohols (R)-2a, (R)-2c and the butanoates (S)-3a-c have been isolated with 98–99% enantiomeric excess (ee) in good yields.