Ag2CO3 (4.11 kg, 15 mol) and molecular sieve powder (4A) (2.50 kg) were added to a stirred solution of 5 (2.70 kg, 15 mol) in CH2Cl2 (18 L). The resulting mixture was stirred for 15 min at ambient temperature, and a solution of 2,3,4,6-O-tetraacetyl-a -D-glucopyranosyl bromide 3 (6.60 kg, 15 mol) in CH2Cl2 (22 L) was added slowly over 40 min under vigorous stirring. The mixture was stirred for 16 h at room temperature. The reaction mixture was filtered, and the filtrate was washed with saturated NaHCO3 (5 L) and brine (5 L), dried over Na2SO4, and then concentrated to afford a syrup. n-Hexane (3.5 L) was slowly added to the syrupy residue under vigorous stirring. The precipitate formed was collected by filtration and dried in vacuo. The solid was dissolved in MeOH (30 L), and MeONa (1.23 kg, 22.5 mol) was added. The mixture was stirred at ambient temperature for about 24 h until TLC (n-hexane= MeOH 3=1) indicated that the material had disappeared. Concentrated HCl was added slowly to adjust the pH to 6–7. The organic layer was separated, dried (Na2SO4), filtered, and concentrated in vacuo. The residue was recrystallized twice from n-hexane=MeOH (5=1), giving 3.83 kg of white powder 1 (80% yield).
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