反应详情

A 25-mL round bottom (RB) flask was purged with nitrogen and charged with (7S)-di-tert-butyl 7-(bis(tert-butoxycarbonyl)amino)-4-hydroxyoct-2-ynedioate (0.04 g, 0.08 mmol), ethyl acetate (5 mL) and 5% palladium on carbon (˜2.0 mg dry weight). The RB flask was evacuated, charged with hydrogen gas in a balloon (to a pressure of 13 psi or approximately 1.0 atmosphere pressure) and stirred for an overnight at room temperature. After this time, the hydrogen was evacuated and nitrogen charged into the RB flask. The catalyst was removed by filtration through a pad of Celite 545 and the filter cake washed with ethyl acetate (10 mL). The filtrate was concentrated under reduced pressure to afford (2S)-di-tert-butyl 2-(bis(tert-butoxycarbonyl)amino)-5-hydroxyoctanedioate (diastereomeric mixture, 0.04 g, 99.3% yield) as an oil. 1H NMR (CDCl3) δ ppm: 4.73 (m, 1H), 3.63 (m, 1H), 2.37 (m, 2H), 2.27-1.56 (m, 6H), 1.51 (s, 18H), 1.45 (2s, 18H). 13C NMR (CDCl3) d ppm: 173.60, 173.58, 170.01, 169.75, 152.58, 152.48, 82.86, 82.82, 81.28, 81.25, 80.42, 80.40, 71.19, 70.65, 58.92, 58.68, 34.37, 34.15, 32.30, 32.22, 32.15, 32.05, 28.07, 28.02, 27.94, 25.69 and 25.55. MS (ESI+): 540 (M+Na)+.

1. customA 25-mL round bottom (RB) flask was purged with nitrogen
2. customThe RB flask was evacuated
3. additioncharged with hydrogen gas in a balloon (to a pressure of 13 psi or approximately 1.0 atmosphere pressure) and
4. customAfter this time, the hydrogen was evacuated
5. additionnitrogen charged into the RB flask
6. customThe catalyst was removed by filtration through a pad of Celite 545
7. washthe filter cake washed with ethyl acetate (10 mL)
8. concentrationThe filtrate was concentrated under reduced pressure