反应详情

温度

-40 °C

Alternately, combine (S)-benzyl-2-oxazolidinone (25 g, 140 mmol) and tetrahydrofuran (250 ml). Add triphenylmethane (30 mg) as an indicator. Cool to about −40° C. Add n-butyl lithium (about 56 ml, 1 M in hexane, 140 mmol) until an orange color persists. After 30 minutes, cool in a dry-ice/acetone bath the a solution of 3,4-dichlorophenylacetic acid trimethylacetyl ester as obtained in Preparation 3 and add by cannula the solution of lithio (S)-benzyl-2-oxazolidinone obtained above. When the addition is complete warm to ambient temperature. After 18 hours, partition the reaction mixture between diethyl ether and a saturated aqueous sodium bicarbonate solution. Separate the layers and dry the organic layer over MgSO4, filter, and evaporate in vacuo to give a residue. Chromatograph the residue on silica gel eluting sequentially is with 5% ethyl acetate/hexane and 10% ethyl acetate/hexane to give (S)-4-benzyl-3-(3,4-dichlorophenyl)acetyl-2-oxazolidinone.

1. customas obtained in Preparation 3
2. customobtained above
3. additionWhen the addition
4. temperatureis complete warm to ambient temperature
5. waitAfter 18 hours
6. custompartition the reaction mixture between diethyl ether
7. customSeparate the layers
8. dry with materialdry the organic layer over MgSO4
9. filtrationfilter
10. customevaporate in vacuo
11. customto give a residue