Reacción #5697

Ecuación de reacción

benzyl chloride

5-fluoroindole

18-crown-6

potassium tert-butoxide

→

1-benzyl-5-fluoroindole

Rendimiento 14.1%

Disolventes

Water

ether

ether

ether

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added
2. 2
   OtroThe layers were separated
3. 3
   ExtracciónThe aqueous layer was extracted with 100 ml of ether
4. 4
   LavadoThe combined ether layers were washed with 50 ml of brine
5. 5
   Secadodried over MgSO4
6. 6
   OtroEvaporation of the solvent
7. 7
   workup.WAITleft 6.95 g of orange oil
8. 8
   OtroThe oil was chromatographed on a 600 g column of silica gel
9. 9
   LavadoThe column was eluted with 30% CH2Cl2 -Skellysolve B and 200 ml fractions
10. 10
    Otrowere collected

Procedimiento

To a solution of 0.8 g (3.03 mmoles) of 18-crown-6 in 100 ml of dry ether was added 3.27 g (29.14 mmoles) of potassium tert-butoxide. The mixture was stirred while a solution of 3.75 g (27.75 mmoles) of 5-fluoroindole in 80 ml of ether was added. The stirring was continued for 0.5 hour. Solid was present. Then 3.69 g (29.15 mmoles) of benzyl chloride in 80 ml of ether was added. The mixture was stirred for 28 hours. Water (100 ml) was added. The layers were separated. The aqueous layer was extracted with 100 ml of ether. The combined ether layers were washed with 50 ml of brine and dried over MgSO4. Evaporation of the solvent left 6.95 g of orange oil. The oil was chromatographed on a 600 g column of silica gel. The column was eluted with 30% CH2Cl2 -Skellysolve B and 200 ml fractions were collected. The fractions were assayed by silica gel tlc (1×4") (30% CH2Cl1 -Skellysolve B). Fractions 11-15 were combined giving 0.88 g (14%) of 1-benzyl-5-fluoroindole as a pale yellow oil which contained a small amount of 1,3-dibenzyl-5-fluorindole.

Fuente