4-Methylmorpholine → (S)-methyl 4-(tert-butoxycarbonylamino)-5-hydroxypentanoate

Participants

Reaction Conditions

Reaction Steps

In a round-bottom flask, (2S)-2-[(tert-butoxy)carbonylamino]-4-(methoxycarbonyl)butanoic acid (78 mmol, 20.36 g) was dissolved in THF (300 mL). The solution was cooled to −10° C. and N-methylmorpholine (78 mmol, 8.58 mL) and ethyl chloroformate (78 mmol, 7.48 mL) were added, followed by sodium borohydride (234 mmol, 8.85 g). The reaction was stirred for 30 min at this temperature and then quenched by slow addition of saturated solution of ammonium chloride until no further evolution of hydrogen was observed. The reaction mixture was then extracted with ethyl acetate and dried over magnesium sulfate. After filtration, solvent was evaporated and the crude material was purified by column chromatography (SiO2, 1:1 n-hexanes/ethyl acetate) to yield the title compound (11.68 g, 61% yield). ES-MS: 248 (M+1).

Provenance & Evidence