Aluminium lithium hydride → tert-butyl N-[(2S)-4-methyl-1-oxopentan-2-yl]carbamate

(S)-(1-Methoxycarbamoyl-3-methyl-butyl)-carbamic acid tert-butyl ester (2.2 g, 8.0 mmol) was dissolved in dry ether (80 mL) under nitrogen atmosphere and cooled to −3° C. in a ice-water-NaCl bath. Solid lithium aluminum hydride (0.31 mg, 8.2 mmol, Aldrich, Milwaukee, Wis.) was then added; the resulting reaction mixture was stirred at that temperature for 25 minutes at which time TLC showed no starting material left, then the reaction was quenched by addition of an aqueous NaHSO4 solution (1.9 g NaHSO4 in 60 mL of water). Two layers were separated; and aqueous layer was extracted with ether (4×100 mL). The combined ether solution was washed successively with 3N aqueous HCl solution (3×100 mL), brine (100 mL), saturated aqueous NaHCO3 solution (3×100 mL), brine (3×100 mL), and was dried over MgSO4. The solution was concentrated in vacuo affording 1.6 g of desired product as a clear oil which was used in the subsequent reaction without further purification.