[C:1]1([CH3:29])[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[O:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1[C:14]([C@@H:16]1[CH2:21][CH2:20][CH2:19][N:18]([C:22]([O:24][C:25]([CH3:28])([CH3:27])[CH3:26])=[O:23])[CH2:17]1)=[O:15]>C1COCC1>[C:1]1([CH3:29])[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[O:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1[C@:14]([C@@H:16]1[CH2:21][CH2:20][CH2:19][N:18]([C:22]([O:24][C:25]([CH3:26])([CH3:28])[CH3:27])=[O:23])[CH2:17]1)([OH:15])[CH2:5][CH2:6][CH2:1][CH2:2][O:7][CH3:8]A 1000-mL, three-necked flask was charged with the (2-(o-tolyloxy)phenyl)((R)-1-(tert-butoxycarbonyl)piperidin-3-yl)methanone (20 g, 0.05 mol) and THF (250 mL). The flask was evacuated and refilled with N2, the mixture was cooled with a dry ice-acetone bath and the Grignard reagent was added dropwise. The mixture was allowed to warm slowly to rt and stirred overnight. After quenching with sat'd aq NH4Cl (500 mL), the mixture was extracted with EtOAc (3×150 mL) and the combined organic layers were dried over Na2SO4. The solvent was removed and the crude product was purified by flash column chromatography to afford the (R)-tert-butyl 3-((S)-1-(2-(o-tolyloxy)phenyl)-1-hydroxy-5-methoxypentyl)piperidine-1-carboxylate (20 g, 83%).
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