Sodium borohydride → 1-Piperidinecarboxylicacid,4-hydroxy-2-methyl-,1,1-dimethylethylester,(2S,4S)-(9CI)

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Reaction Steps

Following the procedure found in Plettenburg, Oliver et. Al (PCT Int. Appl., 2007012421), sodium borohydride (213 mg, 5.6 mmol) was added portion-wise to a solution of tert-butyl 2-methyl-4-oxopiperidine-1-carboxylate (1.0 g, 4.7 mmol) in ethanol (10 mL). The mixture was stirred at room temperature for 2 h. The solution was concentrated in vacuo and then partitioned between water (40 mL) and ethyl acetate (40 mL). The aqueous layer was extracted twice with ethyl acetate (40 mL). The combined organic layers were washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via column chromatography on silica gel (Biotage 50 g column, gradient elution with 40-50% ethyl acetate in hexanes) to afford (rac)-tert-butyl (cis)-4-hydroxy-2-methylpiperidine-1-carboxylate (367 mg, 36%) and (rac)-tert-butyl (trans)-4-hydroxy-2-methylpiperidine-1-carboxylate (205 mg, 20%) as white solids.

Provenance & Evidence