C1(C)C=CC=CC=1.[F:8][C:9]1[CH:10]=[C:11]([CH:27]=[CH:28][CH:29]=1)[C:12]([C@@H:14]1[CH2:19][CH2:18][CH2:17][N:16]([C:20]([O:22][C:23]([CH3:26])([CH3:25])[CH3:24])=[O:21])[CH2:15]1)=[O:13].CO>C1COCC1.CCOC(C)=O>[F:8][C:9]1[CH:10]=[C:11]([C@H:12]([OH:13])[CH:14]2[CH2:19][CH2:18][CH2:17][N:16]([C:20]([O:22][C:23]([CH3:25])([CH3:24])[CH3:26])=[O:21])[CH2:15]2)[CH:27]=[CH:28][CH:29]=1To a solution of 1M R-CBS-oxazaborolidine in toluene (33 mL, 33 mmol, 0.15 eq) and 10 M BH3 in THF (22 mL, 0.22 mol, 1.0 eq) at −15° C. under nitrogen was added dropwise a solution of (R)-tert-butyl 3-(3-fluorobenzoyl)piperidine-1-carboxylate (67.5 g, 0.22 mol) in anhydrous THF (300 mL). After addition, the reaction mixture was stirred for 1 hr at rt. Methanol (200 mL) was added dropwise carefully at 0° C. The solvent was removed under reduced pressure to provide the crude product. The crude product was dissolved in EtOAc until the alcohol was just dissolved (about 5 mL/1 g), the solvent was removed on the rotary evaporator until a few crystals appeared. To the above solution was added petroleum ether (about 300 mL) under stirring, which was allowed to stir at rt for 2 hr and then filtered, the crystals were washed with petroleum ether and re-crystallized to afford the pure R)-tert-butyl 3-((R)-(3-fluorophenyl)(hydroxy)methyl)piperidine-1-carboxylate (26 g, 39%).
読み込み中…
