反应详情

温度

2.5 °C

To a solution of compound 21B (1.56 g, 10 mmol) in CHCl3 (30 mL) cooled to 0-5° C. was added portionwise tetrabutylammonium tribromide (434 mg, 9.0 mmol). After addition, the reaction was stirred at 0-5° C. for 5 min, then quenched with saturated aqueous NaHCO3 (30 mL) and 5% aqueous Na2S2O3 (30 mL). The mixture was stirred at rt for 10 min, then extracted with CH2Cl2 (3×). The combined organics were washed with brine, dried (Na2SO4), filtered and concentrated. The residue was chromatographed (silica gel), eluting with 20-60% EtOAc/hexane to give the title compound (0.75 g, 32% yield).

1. additionAfter addition
2. customquenched with saturated aqueous NaHCO3 (30 mL) and 5% aqueous Na2S2O3 (30 mL)
3. stirringThe mixture was stirred at rt for 10 min
4. extractionextracted with CH2Cl2 (3×)
5. washThe combined organics were washed with brine
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated
9. customThe residue was chromatographed (silica gel)
10. washeluting with 20-60% EtOAc/hexane