反应详情

温度

0 °C

A mechanically stirred, cooled (-78° C.) solution of the oxazolidinone of Step 5 (32.3 g, 250 mmol) in anhydrous THF (830 mL) was metalated with 163 mL (1.6M in hexane, 261 mmol) of n-BuLi and treated with freshly distilled butanoyl chloride (28.1 mL, 271 mmol). The reaction mixture was warmed to 0° C. and stirred for 0.5 h. Excess acid chloride was hydrolyzed by the addition of 1M aqueous K2CO3 (165 mL) followed by stirring the resultant two-phase mixture for 1 h at r.t. Volatiles were removed in vacuo and the product was extracted into CH2Cl2 (3x). The combined organic extracts were successively washed with H2O and brine, dried over MgSO4 and concentrated to give the title compound as a pale yellow oil (52.1 g, quantative). A portion of this crude product was purified by flash chromatography on silica with EtOAc:hexane 1:4 to give a colorless liquid.

1. stirringstirred for 0.5 h
2. customVolatiles were removed in vacuo
3. extractionthe product was extracted into CH2Cl2 (3x)
4. washThe combined organic extracts were successively washed with H2O and brine
5. dry with materialdried over MgSO4
6. concentrationconcentrated