Acetic Acid → 1-O-Acetyl-5-O-t-butyldiphenylsilyl-4-thio-2,3-dideoxyribofuranose

Participants

Reaction Steps

A solution of 9 (1 g, 2.25 mmol) in 14 mL dry hexane and 2 mL toluene was cooled to -78° C. under nitrogen. A 1.5M toluene solution of Dibal-H (3.0 mL, 4.5 mmol) was added over a 2 minute period with stirring continued for an addition 30 minutes. The reaction was quenched with 1.2 mL methanol and allowed to reach 25° C. Then 2.5 mL of saturated NaHCO3 solution was added followed by 1.5 mL ethyl acetate. The mixture was dried with MgSO4. The solids were removed by filtration and washed with ethyl acetate. After removal of solvent in vacuo the residue was redissolved in 20 mL dichloromethane and treated with DMAP (10 mg), pyridine (0.9 mL, 10 mmol) and acetic acid (0.47 mL, 5 mmol) with stirring under nitrogen overnight. The reaction mixture was shaken with 50 mL water, then 50 mL of 1% NaHCO3. After drying (MgSO4), the solvent was removed in vacuo and the residue purified by flash chromatography with 8:1 -hexane/ethyl acetate: yield 0.78 g (83%) of a viscous oil; FAB MS 357 (M-t-butyl)+ ; 1H NMR (CDCl3) δ 7.68 (m, 4, ArH), 7.4 (m, 6, ArH), 6.0 (m, 1, ArH), 3.75 (m, 1, H-5), 3.5 (m, 1, H-4), 3.5 (m, 1, H-5), 2.15 (m, 2, CH2), 2.0 (2s, 3, aromatic acetyls), 1.9 (m, 2, CH2), 1.05 (s, 9, t-butyl).

Provenance & Evidence