Pyridine → ((3aR,5R,6S,6aR)-6-hydroxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)methyl benzoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 1,2-O-isopropylidene-α-D-xylofuranose 1 (30 g, 0.15 mol) in 360 mL of CH2Cl2 was cooled to 0° C. and to it was added 20 mL (0.23 mol) of pyridine and a catalytic amount (1.0 g) of N, N-dimethylaminopyridine. The resulting mixture was stirred at 0° C. for 10 min, at which time 20 mL (0.17 mol) benzoyl chloride was added to it dropwise over a period of 30 min. The reaction mixture was stirred at 0° C. for an additional 30 min and then quenched by the addition of 200 mL a saturated solution of NH4Cl. The reaction was allowed to warm to room temperature, the layers were separated, and the aqueous layer was extracted with 3×50 mL of CH2Cl2. The combined organic extracts were washed with 3×50 mL of a 10% aqueous solution of CuSO4, 2×50 mL of water and brine. The organic solution was dried over anhydrous MgSO4, filtered and concentrated. The crude product mixture was purified by chromatography on silica gel to afford 44.3 g (95% yield) of 2 as a colorless liquid: Rf 0.54 (60% EtOAc/hexane); 1H-NMR (CDCl3) δ 8.03 (m, 2H), 7.40-7.68 (m, 3H), 5.97 (d, 1H, J=3.6 Hz), 4.80 (m, 1H), 4.61 (d, 1H, J=3.4 Hz), 4.37 (m, 2H), 4.20 (s, broad, 1H), 3.35 (broad, 1H), 1.50 (s, 3H), 1.32 (s, 3H).

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