Hydrochloric Acid → tert-Butyl (4-hydroxy-2-methylbutan-2-yl)carbamate

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Reaction Conditions

Reaction Steps

At 0° C., ethyl chloroformate (1.10 ml, 11.5 mmol) was given dropwise to a solution of 3-tert-butoxycarbonylamino-3-methylbutanoic acid (2.50 g, 11.5 mmol) and triethylamine (1.92 ml, 13.8 mmol) in THF (10 ml). The solution was stirred for 40 min at 0° C. The obtained precipitate was filtered off and washed with THF (20 ml). The liquid was immediately cooled to 0° C. A 2M solution of lithium boronhydride in THF (14.4 ml, 28.8 mmol) was added dropwise. The solution was stirred at 0° C. for 2 h, and then warmed to room temp. over a period of 4 h. It was cooled to 0° C. Methanol (5 ml) was added carefully. 1N Hydrochloric acid (100 ml) was added. The solution was extracted with ethyl acetate (2×100 ml, 3×50 ml). The combined organic layers were washed with saturated solution of sodium hydrogencarbonate (100 ml) and dried over magnesium sulfate. The solvent was removed in vacuo. The crude product was chromatographed on silica (110 g) with ethyl acetate/heptane 1:2 to give 1.84 g of 3-hydroxy-1,1-dimethylpropylcarbamic acid tert-butyl ester.

Provenance & Evidence