New Stereoconservative Syntheses of β,β,β- and γ,γ,γ-Trifluoro-α-amino, α-Hydroxy, and α-Mercapto Acids and Their Incorporation into a Peptide and Depsipeptide Fragment
New Stereoconservative Syntheses of β,β,β- and γ,γ,γ-Trifluoro-α-amino, α-Hydroxy, and α-Mercapto Acids and Their Incorporation into a Peptide and Depsipeptide Fragment
Syntheses of (R)-4,4,4-trifluoro-2-mercaptobutyric acid from (S)-malic acid via a Mitsunobu reaction and from (rac)-thiomalic acid on enzymatic resolution, using Pseudomonas cepacia (Amano lipase PS), are described. A new method for direct determination of ees for (R)- and (S)-4,4,4-trifluoro-2-mercaptobutyric acid derivatives by HPLC on a polysaccharide phase is disclosed. (C) 2000 Elsevier Science Ltd. All rights reserved.