Reaction Steps
To a solution of 1-deoxy-1-(phenylthio)-β-D-galactopyranose (0.38 g, 1.4 mmol) in 25 mL of pyridine, pivaloyl chloride (1.75 mL, 14.0 mmol) and DMAP (0.200 g, 1.40 mmol) are added. The reaction mixture is stirred at 90-100° C. for 8 h. Pyridine is removed under reduced pressure, and the residue is dissolved in 100 mL of CH2Cl2 and washed with dilute HCl (100 mL), H2O (100 mL), dried over Na2SO4, filtered, concentrated and purified by flash chromatography (10% EtOAc/hexane) to give 0.65 g (76%) of 1-deoxy-1-(phenylthio)-2,3,4,6-tetra-O-pivaloyl-β-D-galactopyranose 40: Rf 0.59 (15% EtOAc/hexane); 1H NMR (CDCl3, 270 MHz) δ 7.97 (d, J=8.9 Hz, 2 H, ArH), 7.70 (t, J=7.3 Hz, 1 H, ArH), 7.60 (t, J=7.3 Hz, 2 H, ArH), 5.39 (t, J=9.9 Hz, 1 H, H-2), 5.30 (d, J=3.0 Hz, 1 H, H-4), 5.10 (dd, J=9.9, 3.0 Hz, 1 H, H-3), 4.57 (d, J=9.9 Hz, 1 H, H-1), 4.05-4.20 (m, 2 H, H-6), 3.79 (dd, J=10.6, 5.9 Hz, 1 H, H-5), 1.25-(s, 9 H), 1.18 (s, 9 H), 1.08 (s, 9H), 0.92 (s, 9 H). 13C NMR (CDCl3, 270 MHz) δ 177.7, 177.0, 176.7, 176.3, 134.4, 134.2, 131.0, 128.7, 89.4, 74.9, 71.7, 65.9, 63.9, 60.5, 38.4, 38.7, 38.6, 27.1.
