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 (3×). 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 (3×)
4. washThe combined organic extracts were successively washed with H2O and brine
5. dry with materialdried over MgSO4
6. concentrationconcentrated