反应详情

To a solution of acetic acid (1R,2R)-benzyloxycyclohexyl-2,5-dioxo-pyrrolidin-3-(R)-yl ester (3a (1.1 g, 3.18 mmol) in MeOH was added 10% Pd—C (110 mg), and the reaction vessel was flushed twice with H2. The reaction mixture was agitated at ambient temperature under H2 (charged balloon). After 4 hours, the reaction mixture was filtered through a pad of Celite. The filtrate was concentrated in vacuo to give acetic acid 1R,2R-hydroxycyclohexyl-2,5-dioxopyrrolidin-3-(R)-yl ester (4a) as a white hygroscopic foam (0.82 g, 99% yield); MS (ES+) 256.1 [M+H]+, 278.0 [M+Na]+, 533.1 [2M+Na]+; 1H-NMR (400 MHz, CDCl3) δ 1.11-1.34 (m, 3H), 1.64-1.75 (m, 3H), 2.02-2.09 (m, 2H), 2.12 (s, 3H, CH3), 2.22 (br s, 1H), 2.63 (dd, 1H, J=18.0 Hz, 4.8 Hz), 3.11 (dd,1H, J=8.8 Hz, J=18 Hz), 3.82 (ddd,1H, J=4.16 Hz, J=10.6 Hz, J=12.8 Hz), 4.16 (ddd, J=4.4 Hz, J=10.4 Hz, J=14.8 Hz), 5.34 (dd, 1H, J=8.8 Hz, J=4.8 Hz); 13C-NMR (100 MHz, CDCl3) δ 20.52, 24.16, 24.98, 27.77, 35.03, 35.40, 58.44, 67.43, 68.40, 170.11, 173.89, 174.08.

1. customthe reaction vessel was flushed twice with H2
2. filtrationthe reaction mixture was filtered through a pad of Celite
3. concentrationThe filtrate was concentrated in vacuo