Efficient Synthesis of 3-<i>R</i>-Boc-amino-4-(2,4,5-trifluorophenyl)butyric Acid

<div><p></p><p>3-<i>R</i>-Boc-amino-4-(2,4,5-trifluorophenyl)butyric acid (<b>9</b>) was obtained from <i>L</i>-methionine in six steps with a total yield of 32%. The α-amino acid segment of <i>L</i>-methionine was transferred to chiral aziridine by amino protection, reduction, hydroxyl derivation, and cyclization. After ring opening of 2,4,5-trifluoro-phenyl magnesium bromide, the methylthiomethyl group was then hydrolyzed to β-amino alcohol and oxidized to the target β-amino acid.</p></div