(E)-(R)-4-tert-butoxycarbonylamino-2-methyl-pent-2-enoic acid ethyl ester → (2R,4R)-4-tert-butoxycarbonylamino-2-methyl-pentanoic acid ethyl ester
Reaktionsgleichung
[CH2:1]([O:3][C:4](=[O:18])/[C:5](/[CH3:17])=[CH:6]/[C@H:7]([NH:9][C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH3:8])[CH3:2]>C(OCC)(=O)C.[Pt]>[CH2:1]([O:3][C:4](=[O:18])[C@H:5]([CH3:17])[CH2:6][C@H:7]([NH:9][C:10]([O:12][C:13]([CH3:14])([CH3:16])[CH3:15])=[O:11])[CH3:8])[CH3:2]Komponenten
4
Versuchsvorschrift
Next, a solution of (E)-(R)-4-tert-butoxycarbonylamino-2-methyl-pent-2-enoic acid ethyl ester (1.83 g, 7.11 mmol) in ethyl acetate (75 mL) is hydrogenated over 10% Pt/C (183 mg) at 1 atm for 18 hours. The catalyst is filtered through Celite and the solvent is removed under reduced pressure. The residue is purified by chiral HPLC to afford (2R,4R)-4-tert-butoxycarbonylamino-2-methyl-pentanoic acid ethyl ester, 1H-NMR (400 MHz, CDCl3); δ ppm 1.13 (t, 3H), 1.18 (m, 3H), 1.26 (t, 3H), 1.43 (s, 9H), 1.81 (s, 1H), 2.50 (m, 1H), 3.72 (m broad, 1H), 4.14 (m, 2H), 4.33 (m broad, 1H).