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0 °C

3,4-Di-O-benzyl-6-O-levulinoyl-D-arabino-hex-1-enitol (2.12 g, 5.0 mmol) was dissolved in CH2Cl2 (5 mL) and cooled to 0° C. A 0.08 M solution of dimethyldioxirane in acetone (75 mL, 6.0 mmol) was added and the reaction mixture was stirred for 15 min. After the solvent was removed in a stream of N2 and the remaining residue dried in vacuo for 15 min at 0° C., 20 mL CH2Cl2 were added. The solution was cooled to −78° C. for 15 min and dibutylphosphate (1.04 mL, 5.25 mmol) was then added dropwise over 5 min. After complete addition, the reaction mixture was warmed to 0° C. and DMAP (2.44 g, 20.0 mmol) and pivaloyl chloride (1.23 mL, 10.0 mmol) were added. The solution was warmed to room temperature over 1 h. The solvent was removed in vacuo and the residue was purified by flash column chromatography on silica gel to afford 3.29 g (90%) of 8 as a colorless oil. 1H NMR (500 MHz) δ 7.34–7.24 (m, 10H), 5.23 (app t, J=7.6, 7.9 Hz, 1H), 5.14 (app t, J=7.9, 9.2 Hz, 1H), 4.81 –4.78 (m, 2H), 4.72 (d, J=11.0 Hz, 1H), 4.57 (d, J=10.7 Hz, 1H), 4.39 (d, J=11.3 Hz, 1H), 4.23 (dd, J=4.0, 12.2 Hz, 1H), 3.67–3.66 (m, 2H), 2.76–2.70 (m, 2H), 2.57–2.54 (m, 2H), 2.19 (s, 3H), 1.67–1.60 (m, 4H), 1.41–1.35 (m, 4H), 1.20 (s, 9H), 0.96–0.90 (m, 6H); 13C NMR (125 MHz) δ 206.4, 177.0, 172.5, 137.9, 137.5, 128.7, 128.6, 128.4, 128.3, 128.2, 128.0, 127.5, 96.6, 96.6, 82.9, 75.3, 75.2, 73.8, 72.9, 68.2, 68.2, 68.0, 68.0, 62.7, 39.0, 38.0, 32.3, 32.3, 32.3, 32.2, 30.0, 27.9, 27.3, 18.8, 18.8, 13.8, 13.7; 31P NMR (120 MHz) δ-1.66.

1. customAfter the solvent was removed in a stream of N2
2. customthe remaining residue dried in vacuo for 15 min at 0° C.
3. addition20 mL CH2Cl2 were added
4. temperatureThe solution was cooled to −78° C. for 15 min
5. additionAfter complete addition
6. temperaturethe reaction mixture was warmed to 0° C.
7. temperatureThe solution was warmed to room temperature over 1 h
8. customThe solvent was removed in vacuo
9. customthe residue was purified by flash column chromatography on silica gel