LIPASE-CATALYZED ASYMMETRIC HYDROLYSIS OF ESTERS HAVING REMOTE CHIRAL PROCHIRAL CENTERS

Enzymatic hydrolysis of prochiral and racemic dithioacetal esters having up to five bonds between the prochiral/chiral center and the ester carbonyl group proceeds with selectivities up to 98% enantiomeric excess when commercially available lipases are used. For lipase from Pseudomonas sp., chemical yields and ee's were better with the substrate having four bonds between the prochiral center and ester carbonyl than with the three-bond or five-bond analogues, demonstrating that selectivity does not necessarily diminish as the distance between the chiral center and the reaction site increases. These findings are the cornerstone of efficient chemoenzymatic syntheses of both enantiomers of a potent LTD4 antagonist.