A solution of methanesulfonyl chloride (0.93 ml, 12 mmol) in DCM (20 ml) was added dropwise over 30 min to a solution of (S)-tert-butyl 1-hydroxypropan-2-ylcarbamate (2.0 g, 11 mmol) and TEA (1.8 ml, 12.5 mmol) in DCM (40 ml). The volatiles were then removed under reduced pressure and the residue was redissolved in ethyl acetate (30 ml) and water (30 ml). The organic layer was washed with an aqueous solution of NaHCO₃ (30 ml, 5%), brine (30 ml) and dried over anhydrous Na₂SO₄. The product was obtained upon removal of the solvent under reduced pressure. Yield 2.1 g (75%).

¹H NMR (400 MHz, 298 K, CDCl₃) δ_H 4.61 (1H, br s, NH), 4.21 (1H, br s, CH₂), 4.15 (1H, br s, ³J_HH = 10.0 Hz, ²J_HH = 4.3 Hz, CH₂), 4.05 – 3.90 (1H, br s, CH), 3.02 (3H, s, SO₃CH₃), 1.44 (9H, s, ^tBu), 1.22 (3H, d, ³J_HH = 6.9 Hz, CHCH₃).

¹³C NMR (100 MHz, 298 K, CDCl₃) δ_C 155.22 (C=O), 72.17 (CH₂), 45.65 (CH), 37.45 (SO₃CH₃), 28.45 (C(CH₃)₃), 17.30 (CHCH₃), no quaternary carbon peak found

MS (ESI⁺) m/z 276.1 ([M+Na]⁺)

IR (cm^-1) ν 3358, 2978, 2937, 1687, 1527, 1463, 1430, 1394, 1368, 1347, 1331, 1301, 1279, 1242, 1159, 1109, 1061, 1031, 996, 972, 941, 927, 900, 850, 812, 779, 743.

K. Higashiura, H. Morino, H. Matsuura, Y. Toyomaki and K. Ienaga, J. Chem. Soc., Perkin Trans. 1, 1989, 1479-1481.http://dx.doi.org/10.1039/p19890001479