Reaktion #166677

Reaktionsgleichung

Pivaloyl chloride

(R)-4-benzyloxazolidin-2-one

triethylamine

n-BuLi

2-(4-Chloro-3-fluorophenyl)acetic acid

→

(R)-4-benzyl-3-(2-(4-chloro-3-fluorophenyl)acetyl)oxazolidin-2-one

Ausbeute 51.5%

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThe above anion solution was stirred for 20 minutes
2. 2
   workup.STIRRINGto stir for one hour at −78° C.
3. 3
   Temperaturwarmed to 0° C. for two hours
4. 4
   SonstigeThe mixture was quenched with the addition of saturated NH4Cl solution (20 mL)
5. 5
   Einengenconcentrated in vacuo
6. 6
   SonstigeThe resulting residue was then partitioned between ethyl acetate and water
7. 7
   ExtraktionThe aqueous layer was extracted once with ethyl acetate
8. 8
   Waschenwashed with brine
9. 9
   Sonstigeseparated
10. 10
    Trocknendried over MgSO4
11. 11
    Filtrationfiltered
12. 12
    Einengenconcentrated in vacuo
13. 13
    SonstigeThe resulting residue was purified by column chromatography (3:1 hexanes:ethyl acetate)

Vorschrift

2-(4-Chloro-3-fluorophenyl)acetic acid (1.00 g, 5.30 mmol) was dissolved in THF (14 mL) at 0° C. and treated with triethylamine (0.81 mL, 5.8 mmol). Pivaloyl chloride (0.69 mL, 5.6 mmol) was then added to the solution, and the mixture was allowed to stir for one hour at 0° C. In a separate flask, (R)-4-benzyloxazolidin-2-one (0.987 g, 5.57 mmol) was dissolved in THF (14 mL) at −78° C. and treated with n-BuLi (2.54 mL, 5.83 mmol). The above anion solution was stirred for 20 minutes and then cannulated into the anhydride at −78° C. The reaction was then allowed to stir for one hour at −78° C., and then warmed to 0° C. for two hours. The mixture was quenched with the addition of saturated NH4Cl solution (20 mL) and concentrated in vacuo. The resulting residue was then partitioned between ethyl acetate and water. The aqueous layer was extracted once with ethyl acetate, and the organic fractions were combined, washed with brine, separated, dried over MgSO4, filtered, and concentrated in vacuo. The resulting residue was purified by column chromatography (3:1 hexanes:ethyl acetate) to give (R)-4-benzyl-3-(2-(4-chloro-3-fluorophenyl)acetyl)oxazolidin-2-one (0.95 g, 51%) as an oil, which solidified upon standing.

Quelle