Reaction Steps
Methyl 3,4-di-O-benzyl-6-O-(4-chlorobenzyl)-β-D-glucopyranoside (0.244 g, 0.481 mmol) was dissolved in 5 mL CH2Cl2. Benzoyl chloride (67 μL, 0.577 mmol) and DMAP (0.118 g, 0.962 mmol) were added and the reaction mixture was stirred at room temperature for 1 h. A 30% EtOAc/Hexanes solution was added (a white precipitate formed) and the solution was filtered through silica, eluted with EtOAc and concentrated. Purification by flash column chromatography on silica gel (25-30% EtOAc/Hexanes) gave 243 mg (84%) of 21 as a white solid. [α]24D: +33.4° (c 1.29, CH2Cl2); IR (thin film) 2865, 1726, 1268, 1089 cm−1; 1H-NMR (CDCl3) δ 8.05 (d, J=7.0 Hz, 2H), 7.59 (t, J=7.3 Hz, 1H), 7.46 (t, J=7.9 Hz, 2H), 7.36-7.29 (m, 8H), 7.26-7.21 (m, 2H), 7.15 (s, 4H), 5.30 (dd, J=7.9, 9.2 Hz, 1H), 4.86 (d, J=10.7 Hz, 1H), 4.77 (d, J=11.0 Hz, 1H), 4.70 (d, J=11.0 Hz, 1H), 4.62 (d, J=12.2 Hz, 1H), 4.59 (d, J=11.0 Hz, 1H), 4.56 (d, J=12.5 Hz, 1H), 4.48 (d, J=7.9 Hz, 1H), 3.86 (dd, J=9.2, 9.2 Hz, 1H), 3.80-3.74 (m, 3H), 3.61-3.58 (m, 1H), 3.50 (s, 3H); 13C-NMR (CDCl3) δ 165.4, 138.0, 137.9, 136.8, 133.5, 133.3, 130.1, 130.0, 129.2, 128.7, 128.6, 128.5, 128.4, 128.2, 128.1, 128.0, 127.8, 102.1, 83.0, 78.1, 75.4, 75.3, 75.2, 73.9, 72.9, 68.9, 57.0; FAB MS m/z (M+Na)+: calcd 625.1969, obsd 625.1973.
