| With 2,4,6-trimethyl-pyridine; silver trifluoromethanesulfonate; In dichloromethane; toluene; at -78 - 20℃; for 13.17h; | To the solution of 819 mg [4-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)phenyl] methanol (3.50 mmol, 1 eq.), 2015 mg l-bromo-2, 3,4, 6-tetra-0-acetyl-a/p-D- mannopyranose (4.90 mmol, 1.4 eq.), 467 mg s-collidine (3.85 mmol, 1.1 eq.) in 100 mL DCM 1708 mg silver trifluoromethanesulfonate (6.65 mmol, 1.9 eq.) in 15 mL toluene was added dropwise at -78 °C and the mixture was stirred at this temperature for 10 minutes. The mixture was let to warm slowly to r.t. (3 hours), then it was stirred for 10 hours. The mixture was filtered through a Celite pad, the filtrate was concentrated. The residue was purified by flash chromatography on silica gel using heptane and ethyl acetate as eluents to give Preparation 4o as first eluted product 1H NMR (500 MHz, DMSO-d6): 7.69 (m, 2H), 7.39 (m, 2H), 5.15-5.10 (m, 3H), 4.96 (d, 1H), 4.71 (d, 1H), 4.57 (d, 1H), 4.15 (dd, 1H), 4.04 (dd, 1H), 3.96 (m, 1H), 2.12-1.91 (s, 12H), 1.29 (s, 12H); and Preparation 4p as later eluted product. 1H NMR (500 MHz, DMSO-d6): 7.63 (m, 2H), 7.31 (m, 2H), 5.68 (d, 1H), 5.32 (dd, 1H), 5.05 (t, 1H), 4.59 (d, lh) 4.54 (dd, 1H), 4.53 (d, 1H), 4.12 (dd, 1H), 4.03 (dd, 1H), 3.94 (m, 1H), 2.01-1.97 (s, 9H), 1.70 (s, 3H), 1.29 (s, 12H) |