反应详情

Phosphorus tribromide (0.4 eq) was added to the alcohol 304 (25 g, 0.13 mol) in THF (100 mL) very slowly at −10° C. and the mixture which resulted was stirred for 15-30 min at the same temperature. By this time all the starting material had disappeared (TLC). The reaction mixture was quenched by addition of ice-cold H2O (100 mL) and then filtered through a Buchner funnel. The filtrate was diluted with brine (100 mL) and extracted with EtOAc (3×300 mL). The combined organic extracts were dried (Na2SO4) and concentrated in vacuo. The crude oil was purified by FCC (20% ethylacetate in hexane) to afford the bromide 305 as a white solid (92%)a: 1H NMR (500 MHz, CDCl3) δ 6.61 (2H, d, J=2.3 Hz), 6.46 (1H, t, J=2.3 Hz), 4.5 (2H, s), 3.85 (6H, s). 13C NMR (125 MHz, CDCl3): δ 161.3, 140.2, 107.4, 101.0, 55.8, 34.1. The spectral data for 305 were in excellent accord with data previously reported on it (Seidel et al., 1990)1. This material was employed directly in the next step.

1. customthe mixture which resulted
2. customThe reaction mixture was quenched by addition of ice-cold H2O (100 mL)
3. filtrationfiltered through a Buchner funnel
4. additionThe filtrate was diluted with brine (100 mL)
5. extractionextracted with EtOAc (3×300 mL)
6. dry with materialThe combined organic extracts were dried (Na2SO4)
7. concentrationconcentrated in vacuo
8. customThe crude oil was purified by FCC (20% ethylacetate in hexane)