反应详情

To a solution of racemic ethyl 4-hydroxy-1-(phenylmethyl)-3-piperidinecarboxylate (37 g, 140 mmol) in N,N-dimethylformamide (250 ml) was added tert-butyldimethylchlorosilane (10.6 g, 70 mmol) and imidazole (5.3 g, 77 mmol) under argon. The reaction was stirred at room temperature for 3 h; water was added and the aqueous phase was extracted with dichloromethane. The organic layer was dried and the solvent was removed under reduced pressure to afford 40 g of crude. The crude was divided into 3 batches (5 g, 17 g, 17 g) and each batch was subjected to column chromatography on silica gel using a hexane and ethyl acetate gradient (0-20% ethyl acetate in hexane). This provided the desired compound (16.67 g, 45%) and ethyl(trans)-4-{[(1,1-dimethylethyl)(dimethyl)silyl]oxy}-1-(phenylmethyl)-3-piperidinecarboxylate (15.8 g, 30%).

1. extractionthe aqueous phase was extracted with dichloromethane
2. customThe organic layer was dried
3. customthe solvent was removed under reduced pressure
4. customto afford 40 g of crude