反应详情

To an oven-dried, N2-purged, 250-mL, round-bottomed flask containing a magnetic stir bar was added the product of Example 192A (3.14 g, 15.0 mmol). Anhydrous t-butanol (50 mL) was added via syringe. Triethylamine (2.62 mL, 1.90 g, 18.75 mmol) was added via syringe. Diphenylphosphorylazide (3.45 mL, 4.40 g, 16.5 mmol) was added via syringe. A reflux condenser with N2-inlet was attached and a heating mantle was applied. The golden solution was heated to reflux and stirred for 8 hours. After cooling to room temperature, the solvent/volatiles were removed by rotary evaporator to give a thick golden oil. The product was purified by flash chromatography (silica gel: 10% ethyl acetate, 90% hexanes—product Rf˜0.6) to give a 3.57 g (85%) of the title compound as a white powder. MS (ESI−) m/z 278.0 (M−H); 1H NMR (DMSO-d6) δ 1.45 (s, 9H), 7.42 (dd, J=9.0, 9.0 Hz, 1H), 7.54 (dd, J=9.2, 5.8 Hz, 1H), 8.95 (br s, 1H).

1. customTo an oven-dried, N2-purged
2. addition250-mL, round-bottomed flask containing a magnetic stir bar
3. customA reflux condenser with N2-inlet was attached
4. temperatureThe golden solution was heated
5. temperatureto reflux
6. customthe solvent/volatiles were removed by rotary evaporator
7. customto give a thick golden oil
8. customThe product was purified by flash chromatography (silica gel: 10% ethyl acetate, 90% hexanes—product Rf˜0.6)