Methanol → tert-Butyl hydrogen (1,5-dihydroxypentan-2-yl)carbonimidate

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Reaction Steps

Lithium borohydride (2.0 M in THF, 4.12 ml, 8.24 mmol) was cooled in an ice bath and a solution of (S)-2-tert-butoxycarbonylamino-pentanedioic acid diethyl ester (0.5 g, 1.65 mmol) in THF (5.5 ml) was added dropwise. The reaction was warmed to room temperature and stirred 16 h. Methanol was added very slowly to the reaction mixture. After a delayed, vigorous gas evolution had subsided, water and ethyl acetate were added. The aqueous layer was extracted with ethyl acetate five times, and the combined organic layers were washed with sodium chloride solution and dried over sodium sulfate. After evaporation, the residue was purified by silica gel chromatography (methanol/dichloromethane) to give 0.3 g (83%) of ((S)-4-hydroxy-1-hydroxymethyl-butyl)-carbamic acid tert-butyl ester. (M+Na)+=242.

Provenance & Evidence