反应详情

To a solution of (3aR,4R,5R,6R,7aS)-6-(((tert-butyldimethylsilyl)oxy)methyl)-4,5-dihydroxyhexahydrobenzo[d]oxazol-2(3H)-one (2.21 g, 7.00 mmol) and 4-dimethylaminopyridine (30 mg, 0.24 mmol) in pyridine (20 mL) at 0° C. was added benzoyl chloride (3.92 g, 27.9 mmol) dropwise. The mixture was stirred at room temperature for 20 h. The reaction was diluted with EtOAc (300 mL), washed with saturated aqueous NaHCO3 water (2×150 mL), 0.5 N HCl (2×100 mL) and brine and dried over MgSO4. The solvent was evaporated to give the crude product. This was purified by basic alumina column, eluted with 10-30% EtOAc in hexanes to provide (3aS,4R,5R,6R,7aS)-6-(((tert-butyldimethylsilyl)oxy)methyl)-2-oxooctahydrobenzo[d]oxazole-4,5-diyl dibenzoate (3.29 g, 90%). 1H NMR (400 MHz, CDCl3) δ 7.92-7.97 (m, 4H), 7.49-7.53 (m, 2H), 7.35-7.39 (m, 4H), 6.07 (s, 1H), 5.53 (t, J=10.1 Hz, 1H), 5.13 (dd, J=9.6 Hz, 6.6 Hz, 1H), 4.91-4.94 (m, 1H), 3.89 (t, J=7.0 Hz, 1H), 3.79 (dd, J=10.0 Hz, 4.0 Hz, 1H), 3.61 (dd, J=10.0 Hz, 2.6 Hz, 1H), 2.40 (dt, J=15.5 Hz, 3.0 Hz, 1H), 2.27-2.36 (m, 1H), 2.03-2.11 (m, 1H), 0.87 (s, 9H), −0.03 (s, 3H), −0.07 (s, 3H).

1. washwashed with saturated aqueous NaHCO3 water (2×150 mL), 0.5 N HCl (2×100 mL) and brine
2. dry with materialdried over MgSO4
3. customThe solvent was evaporated
4. customto give the crude product
5. customThis was purified by basic alumina column
6. washeluted with 10-30% EtOAc in hexanes