反应详情

A stirred solution of 3-Fluoro-4-oxo-piperidine-1-carboxylic acid tert-butyl ester (2.00 g, 9.21 mmol) in methanol (20 ml) and acetic acid (1 ml) was treated with benzyl amine (1.106 ml, 10.013 mmol) and stirred at ambient temperature for three hours. The mixture was then treated with sodium cyanoborohydride (0.8678 g, 13.81 mmol) and left to stand overnight. The reaction was quenched with a saturated solution of sodium bicarbonate (20 ml) and extracted with three portions of dichloromethane (50 ml). Combined organic layers were dried with magnesium sulfate and concentrated under vacuum to give crude product. Purification by column chromatography on silica gel (gradient: 0 to 60% ethyl acetate in heptane) gave 734 mg (26%) of trans-4-benzylamino-3-fluoro-piperidine-1-carboxylic acid tert-butyl ester and 653 mg (23%) of cis-4-benzylamino-3-fluoro-piperidine-1-carboxylic acid tert-butyl ester.

1. waitleft
2. waitto stand overnight
3. customThe reaction was quenched with a saturated solution of sodium bicarbonate (20 ml)
4. extractionextracted with three portions of dichloromethane (50 ml)
5. dry with materialCombined organic layers were dried with magnesium sulfate
6. concentrationconcentrated under vacuum
7. customto give crude product
8. customPurification by column chromatography on silica gel (gradient: 0 to 60% ethyl acetate in heptane)