Water → benzyl [(2S)-3-oxobutan-2-yl]carbamate

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Reaction Conditions

Reaction Steps

Under argon, 1000 mg of benzyl {(2S)-1-[methoxy(methyl)amino]-1-oxopropan-2-yl}carbamate (Example 148A, 3.8 mmol, 1 equivalent) were dissolved in 19.5 ml of THF and cooled to −78° C. At this temperature, 4 ml of 1.4 M methylmagnesium bromide solution in 1:3 THF/toluene (6 mmol, 1.5 equivalents) were added slowly. The mixture was stirred at −78° C. for 5 min and at RT for 1 h and allowed to stand at RT overnight. 0.27 ml of water was then added with ice cooling, and the mixture was concentrated. The residue was diluted with water and 1 N aqueous hydrochloric acid solution and extracted four times with ethyl acetate. The organic phase was washed with saturated aqueous sodium bicarbonate solution and with saturated aqueous sodium chloride solution, dried over magnesium sulphate, filtered and concentrated. This gave 813 mg (88% of theory; purity 90%) of the title compound.

Provenance & Evidence