To a mixture of methyl β-D-ribofuranoside (Sigma Chemical Co., 460 mg, 2.8 mmol) and anhydrous methylene chloride (20 ml) were added triethylamine (0.468 ml, 3.36 mmol), t-butyldiphenylchlorosilane (0.9 ml, 3.46 mmol), and DMAP (13.7 mg, 0.112 mmol) successively at room temperature. The reaction mixture was stirred for 18 h at room temperature under nitrogen. The reaction mixture was washed with water (20 ml), saturated ammonium chloride (20 ml), and brine (20 ml), dried over anhydrous MgSO4, filtered, and concentrated to dryness. The residue was separated by silica gel column chromatography (CHCl3 --MeOH, 50:1) to yield 1-O-methyl 5-(t-butyldiphenylsilyl)-β-D-ribofuranoside [Rf =0.48 (CHCl3 --MeOH, 10:1), 618 mg, 54.8%] as a thick syrup. 1H NMR (DMSO-d6) d 0.96 (s, 9H, t-Bu), 3.22 (s, 3H, --OCH3), 3.61 (dd, J=11.0 and 5.3 Hz, 1H), 3.74 (d, J=4.4 Hz, 1H), 3.81 (dd, J=11.0 and 2.7 Hz, 1H), 3.90 (m, 1H), 4.00 (m, 1H), 4.68 (s, 1H, H-1'), 4.84 (br s, 1H, exchangeable with D2O, OH), 5.05 (br s, 1H, exchangeable with D2O, OH), 7.45 and 7.67 (m, 10H, Ph2). Anal. Calcd for C22H30O5Si: C, 65.64; H, 7.51; Found: C, 65.73; H, 7.55.
