反应详情

温度

0 °C

To a solution of (3aS,4R,5R,6R,7aS)-4,5-bis(benzyloxy)-6-((benzyloxy)methyl)hexahydrobenzo[d]oxazol-2(3H)-one (7.35 g, 15.5 mmol) in DCM (80 mL) at −78° C. was added a solution of BCl3 in DCM (1.0 M, 53 mL, 53 mmol). The mixture was slowly warmed up to 0° C. and stirred at this temperature for 4 h. The reaction was cooled to −78° C. again and a 1:1 mixture of MeOH-DCM (50 mL) was added dropwise to quench the reaction. Solvents were evaporated and the residue was treated with MeOH for three more times. The crude product was purified by silica gel column chromatography, eluted with 5%-15% MeOH in DCM to give (3aR,4R,5R,6R,7aS)-4,5-dihydroxy-6-(hydroxymethyl)-hexahydrobenzo[d]oxazol-2(3H)-one (2.99 g, 95%) as a white solid. 1H NMR (400 MHz, MeOD) δ 4.68-4.71 (m, 1H), 3.72 (dd, J=10.8 Hz, 3.4 Hz, 1H), 3.64 (dd, J=10.8 Hz, 5.2 Hz, 1H), 3.46 (t, J=7.2 Hz, 1H), 3.32 (t, J=8.7 Hz, 1H), 3.19 (t, J=9.4 Hz, 1H), 2.17-2.25 (m, 1H), 1.64-1.75 (m, 2H).

1. temperatureThe reaction was cooled to −78° C. again
2. additionwas added dropwise
3. customto quench
4. customthe reaction
5. customSolvents were evaporated
6. additionthe residue was treated with MeOH for three more times
7. customThe crude product was purified by silica gel column chromatography
8. washeluted with 5%-15% MeOH in DCM