反应详情

To a degassed solution of (S)-dibenzyl 2-(1-benzyl-5-(tert-butoxycarbonyl)pyrrolidin-2-ylidene)succinate (1500 mg, 2.70 mmol) was added 10% Pd/C (900 mg, 0.846 mmol) and ammonium formate (2,550 mg, 40.5 mmol) in MeOH (20 ml). The reaction mixture was then heated to reflux under argon. After 12 hrs, heating was stopped and the reaction mixture was left to stand at rt overnight. The next day another 0.5 g of ammonium formate was added to the reaction and reaction was heated for another 5 hrs. The reaction mixture was diluted with MeOH and filtered. The catalyst was rinsed with MeOH and the filtrate was concentrated to give a yellow solid. CH2Cl2 was added to the residue and the mixture was stirred for 5 min. The mixture was then filtered to remove ammonium formate. The filtrate was concentrated to give 3-((2R,5S)-1-benzyl-5-(tert-butoxycarbonyl)pyrrolidin-2-yl)propanoic acid (200 mg, 0.60 mmol, 22.2% yield) as a yellow syrup. 1H NMR (400 MHz, CDCl3) δ ppm 8.20 (2 H, d, J=13.7 Hz), 7.36-7.26 (5 H, m), 3.97 (1 H, d, J=13.7 Hz), 3.75 (1 H, d, J=13.7 Hz), 3.36 (1 H, t, J=7.4 Hz), 3.14-3.05 (1 H, m), 2.61-2.52 (1 H, m), 2.40-2.31 (1 H, m), 2.10-1.98 (1 H, m), 1.96-1.77 (4 H, m), 1.77-1.65 (1 H, m), 1.34 (9 H, s).

1. temperatureThe reaction mixture was then heated
2. temperatureto reflux under argon
3. temperatureheating
4. waitthe reaction mixture was left
5. waitto stand at rt overnight
6. temperaturewas heated for another 5 hrs
7. filtrationfiltered
8. washThe catalyst was rinsed with MeOH
9. concentrationthe filtrate was concentrated
10. customto give a yellow solid
11. filtrationThe mixture was then filtered
12. customto remove ammonium formate
13. concentrationThe filtrate was concentrated