反应详情

To a solution of alcohol from Step B (6.95 g, 21.9 mmol) and N,N-diisopropylethylamine (11.4 mL, 65.7 mmol) in methylene chloride (300 mL)/DMF (50 mL) was added di-tert-butyl dicarbonate (6.69 g, 30.7 mmol) at 0° C. The reaction was stirred for 24 hours, then methanesulfonic anhydride (7.63 g, 43.8 mmol) was added in one portion. The reaction was stirred for 3 hours at 25° C. and 16 hours at reflux. The reaction was poured onto saturated aqueous sodium bicarbonate and extracted with methylene chloride (3×100 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo to provide a yellow oil. The crude product was purified by column chromatography (50→70% ethyl acetate/hexane) to provide the title compound as a yellow oil.

1. stirringThe reaction was stirred for 3 hours at 25° C. and 16 hours
2. temperatureat reflux
3. extractionextracted with methylene chloride (3×100 mL)
4. dry with materialThe combined organic layers were dried over sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customto provide a yellow oil
8. customThe crude product was purified by column chromatography (50→70% ethyl acetate/hexane)