1-Piperidinecarboxylic acid, 3-fluoro-4-hydroxy-, 1,1-dimethylethyl ester

211108-50-8

373604-28-5

General procedure for the synthesis of tert-butyl 3-fluoro-4-hydroxypiperidine-1-carboxylate from tert-butyl 3-fluoro-4-oxopiperidine-1-carboxylate: To a solution of tert-butyl 3-fluoro-4-oxopiperidine-1-carboxylate (2.0 g, 9.2 mmol, 1.0 equiv.) in methanol (15 mL) was slowly added sodium borohydride (525 mg, 13.8 mmol, 1.5 equiv.) at 0 °C. 1.5 equiv). The reaction mixture was stirred at room temperature for 4 hours. After the reaction was completed, the reaction mixture was diluted with water (80 mL) and extracted with ethyl acetate (100 mL x 2). The organic layers were combined, washed with brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product obtained was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1) to give tert-butyl 3-fluoro-4-hydroxypiperidine-1-carboxylate (1.8 g, 90% yield) as a yellow solid.ESI-MS (M + H-56): 164.1.