An efficient chemoenzymatic approach to (S)-γ-fluoroleucine ethyl ester

…, PN Devine, V Upadhyay, RA Desmond…

Index: Limanto, John; Shafiee, Ali; Devine, Paul N.; Upadhyay, Veena; Desmond, Richard A.; Foster, Bruce R.; Gauthier Jr., Donald R.; Reamer, Robert A.; Volante Journal of Organic Chemistry, 2005 ,  vol. 70,  # 6  p. 2372 - 2375

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Citation Number: 29

Abstract

An asymmetric synthesis of (S)-γ-fluoroleucine ethyl ester 1 is described. The key transformation involves a lipase-catalyzed dynamic ring-opening of 2-(3-butenyl) azlactone 7b with EtOH to give amide ester (S)-6b in 84% enantiomeric excess. Removal of the N- pentenoyl group with N, N'-dibromodimethylhydantoin in the presence of trifluoroacetic acid afforded the titled compound, which was isolated as its hydrogen sulfate salt in 75% yield ...