4-Methylmorpholine → Tert-butyl (s)-(1-hydroxypent-4-en-2-yl)carbamate

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Reaction Conditions

Reaction Steps

N-methylmorpholine (15.25 ml) and ethyl chloroformate (12.60 ml) were added to a solution of (S)-2-((tert-butoxycarbonyl)amino)pent-4-enoic acid (25.0 g) in THF (250 ml) at −15° C. After stirring the mixture at −15° C. for 15 minutes, the generated insoluble matter was filtered off. A solution of sodium borohydride (3.23 g) in water (32 ml) was added to the filtrate at −15° C., and the mixture was stirred at −15° C. for 1 hour. A saturated aqueous ammonium chloride solution was added thereto, and the mixture was stirred at room temperature for 30 minutes. Ethyl acetate was added thereto to separate the organic layer. The organic layer was washed with a 0.5 N aqueous potassium hydrogensulfate solution, water, a 0.5 N aqueous sodium hydroxide solution, and a saturated sodium chloride solution; and dried over anhydrous sodium sulfate. The solvent was then distilled off under reduced pressure. The resulting residue was purified by silica gel column chromatography (developing solvent: hexane/ethyl acetate) to obtain the title compound as a light-yellow, oily substance (11.93 g).

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