Methanesulfonyl chloride → 3-(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)propyl methanesulfonate

To a solution of 3-(2,3,4-tri-O-benzyl-α-L-fucopyranosyl)propanol [ML-36 step D] (10.6 g, 22.2 mmol) and Hunig's Base (4.66 mL, 26.7 mmol) in anhydrous DCM (100 mL) cooled in an ice bath was added dropwise methanesulfonyl chloride (1.9 mL, 24.5 mmol). After complete addition the mixture was stirred at ice bath temperature for 1 hour. Mixture washed with water (100 mL), sat. NaCl (50 mL); dried over Na2SO4, filtered and evaporated to give the title compound (12.6 g, 100%). 1H NMR (CDCl3) δ 7.37 (15H, m), 4.80 (2H, m), 4.68 (2H, m), 4.63 (1H, d, J=11.8 Hz), 4.53 (1H, J=11.8 Hz), 4.22 (2H, m), 4.00 (1H, d, J=9.8 Hz), 3.94 (1H, m), 2.99 (3H, s), 1.88 (1H, m), 1.75 (2H, m), 1.62 (1H, m), 1.31 (3H, d, J=6.6 Hz).