Reacción #76452

Ecuación de reacción

lithium diisopropylamide

methyl 2-[2-(2,2-dimethylpropyl)benzoxazol-5-yl]propionate

N-fluorobenzensulfonimide

→

methyl 2-[2-(2,2-dimethylpropyl)benzoxazol-5-yl]-2-fluoropropionate

Rendimiento 78.0%

Disolventes

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroThe cooling bath was removed
2. 2
   Temperaturato warm to room temperature
3. 3
   workup.STIRRINGwith stirring over 1½ hours
4. 4
   OtroThe mixture was quenched with water
5. 5
   Extracciónextracted with ethyl acetate
6. 6
   ExtracciónThe organic extract
7. 7
   Lavadowas washed with brine
8. 8
   Secadodried over anhydrous magnesium sulfate
9. 9
   Filtraciónfiltered
10. 10
    Otrothe filtrate was evaporated in vacuo
11. 11
    OtroThe residue was purified by flash column chromatography on silica gel
12. 12
    Lavadoeluting with ethyl acetate:dichloromethane 1:99

Procedimiento

A solution of lithium diisopropylamide (2.0M solution in tetrahydrofuran/ethylbenzene/heptane, 4.55 ml, 0.009 mol) was added, dropwise, to a solution of methyl 2-[2-(2,2-dimethylpropyl)benzoxazol-5-yl]propionate (2.5 g, 0.009 mol) in tetrahydrofran (65 ml) at −70° C. under a nitrogen atmosphere and the mixture was stirred at −70° C. for 1 hour. A solution of N-fluorobenzensulfonimide (2.9 g. 0.009 mol) in tetrahydrofuran (15 ml) was added and the mixture was stirred at −70° C. for a further 1 hour. The cooling bath was removed and the reaction mixture was allowed to warm to room temperature, with stirring over 1½ hours. The mixture was quenched with water, acidified with dilute aqueous hydrochloric acid and extracted with ethyl acetate. The organic extract was washed with brine, dried over anhydrous magnesium sulfate, filtered and the filtrate was evaporated in vacuo. The residue was purified by flash column chromatography on silica gel, eluting with ethyl acetate:dichloromethane 1:99, to give methyl 2-[2-(2,2-dimethylpropyl)benzoxazol-5-yl]-2-fluoropropionate (2.06 g).

Fuente