To a solution of the commercially available benzyl {(2S)-1-[methoxy(methyl)amino]-1-oxopropan-2-yl}carbamate (5.48 g, 20.58 mmol) and 3-bromo-5-fluorobenzotrifluoride (5 g, 20.58 mmol) in THF (52 ml) at −30° C. was added isopropylmagnesium chloride (20.58 ml, 41.2 mmol) dropwise under nitrogen. Removed the cold bath and allowed the reaction to age overnight to ambient temperature. The crude was cooled to −20° C. followed by addition of HC (1N, ice bath cold). The resulting mixture was worked up with brine, extracted with ethyl acetate, dried over Na2SO4, filtered and evaporated. The pot residue was purified by flash chromatography (SiO2, Biotage 65i cartridge). The column was eluted by an ethyl acetate/hexanes mixture (0% to 40% ethyl acetate). Related fractions were pooled and evaporated under reduced pressure to afford a yellow oil of 5.4655 g as the titled compound. 1H-NMR (CDCl3, 500 MHz) δ 8.03 (s, 1H), 7.86 (d, J=8.5 Hz, 1H), 7.57 (d, J=8 Hz, 1H), 7.38-7.30 (m, 5H), 5.7 (d, J=7.5 Hz, 1H), 5.3 (ps quintet, J=7.5 Hz, 1H), 1.45 (d, J=7 Hz, 3H).
