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

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Reaction Steps

213 mg (5.6 mmol) of NaBH4 were added portionwise at 0° C. to a solution of 1.0 g (4.7 mmol) 1-boc-2-methyl-piperidin-4-on in 10 mL of ethanol. The mixture was stirred at room temperature for 2 h. The solvent was removed by distillation and the remainder was dissolved in water and ethyl acetate. The aqueous layer was extracted twice with ethyl acetate and the combined organic layers were dried over Na2SO4. After filtration the solvent was removed by distillation and the crude product was purified by column chromatography (n-heptane/ethyl acetate 1/1) to yield 367 mg (36%) of the cis-isomer 18 and 205 mg (20%) of the trans-isomer 19 in addition to 97 mg (10%) mixture of both isomers.

Provenance & Evidence