反应详情

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); 6 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).

1. filtrationThe catalyst is filtered through Celite
2. customthe solvent is removed under reduced pressure
3. customThe residue is purified by chiral HPLC