Reaktion #49212
ord-9d0225a190ec4ebeb569bf324156df4c
Reaktionsgleichung
Edukte
Reagenzien
Reaktionsbedingungen
Aufarbeitung
- 1Sonstigewas brought to 0° C.
- 2workup.ADDITIONWhen the addition
- 3workup.STIRRINGthe mixture was stirred at −78° C. for 5 min.
- 4Temperaturto warm to rt
- 5workup.STIRRINGAfter stirring at rt for 4 h. the mixture
- 6Einengenwas concentrated in vacuo
Vorschrift
Step A (5): 2R,4R)-tert-butyl 2-((1S,2S)-2-(3,5-difluorobenzyl)-3-((S)-4-benzyl-2-oxooxazolidin-3-yl)-1-hydroxy-3-oxopropyl)-4-(allyloxy)pyrrolidine-1-carboxylate. To a solution of (S)-4-benzyl-3-(3-(3,5-difluorophenyl)propanoyl)oxazolidin-2-one (Preparation B, 1.47 g, 4.27 mmol) in CH2Cl2 (15 ml) at −78° C. was added Bu2BOTf (5.12 ml, 5.12 mmol, 1M in CH2Cl2) and Hunig's base (1.12 ml, 6.41 mmol). The resulting mixture was brought to 0° C. and stirred for 30 min. The mixture was again cooled to −78° C. and a solution of (2R,4R)-tert-butyl 4-(allyloxy)-2-formylpyrrolidine-1-carboxylate (Step A (4), 1.09 g, 4.27 mmol) in CH2Cl2 (10 ml) was added dropwise. When the addition was complete, the mixture was stirred at −78° C. for 5 min., then was allowed to warm to rt. After stirring at rt for 4 h. the mixture was concentrated in vacuo. Flash chromatography (silica gel, 0-75% ethyl acetate/hexane) gave 1.22 g (48%) of (2R,4R)-tert-butyl 2-((1S,2S)-2-(3,5-difluorobenzyl)-3-((S)-4-benzyl-2-oxooxazolidin-3-yl)-1-hydroxy-3-oxopropyl)-4-(allyloxy)pyrrolidine-1-carboxylate as a slightly yellow oil: 1H NMR (CDCl3, 300 MHz) δ 1.49 (9H, s), 2.03-2.22 (2H, m), 2.31 (1H, d, J=12 Hz), 2.98 (1H, dd, J=3, 15 Hz), 3.07 (1H, t, J=12 Hz), 3.42-3.57 (3H, m), 3.97-4.11 (8H, m), 4.57 (2H, brd s), 5.17-5.30 (2H, m), 5.81-5.94 (1H, m), 6.61 (1H, t, J=9 Hz), 6.90 (2H, brd s), 7.00 (2H, brd s), 7.26 (3H, m). HPLC retention time: 2.04 min (method A). MS (ESI) (M+H)+ 601.37.