To a suspension of (14) (6.68 g, 22.95 mmol) in 150 mL of methanol was added 8.05 mL of a 2.85 M methanolic potassium hydroxide. The mixture was stirred for one minute and then diluted with 100 mL of toluene and evaporated. The solid potassium salt of 1 was dried under vacuum. The potassium salt was suspended in 75 mL of anhydrous DMF and then diluted with 420 mL of anhydrous acetonitrile. 1-Chloro-1,2-dideoxy-3,5-di-O-toluoylribofuranose (8.95 g, 22.95 mmol) was immediately added and the reaction mixture was stirred at room temperature under argon for 1 h. and then filtered. The filtrate was evaporated and the residual foam was recrystallized twice from methanol: 6.59 g (45%) yield; TLC (1:1, ethyl acetate/hexane), Rf=0.52; 1H NMR (DMSO-d6) δ 7.93 and 7.37 (8H, m and d, J=7.9 Hz for the d, aromatic), 7.10 (2H, br s, 6-amino), 6.51 (1H, t, J=6.6 Hz, 1′-H), 5.69 (1H, m, 3′-H), 4.44 (3H, m, 4′- and 5′-Hs), 3.99 (3H, s, 4-methoxy), 3.19 and 2.63 (2H, 2×m, 2′-Hs), 2.40 and 2.38 (6H, 2×s, toluoyl methyl protons).
