Reacción #1221

Ecuación de reacción

5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-bromoanthracene

magnesium

ethyl 2-bromo-4-thiophenecarboxylate

→

ethyl 2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-anthryl)-4-thiophenecarboxylate

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONOnce the addition
2. 2
   Temperaturathe mixture was heated
3. 3
   Temperaturaat reflux for one hour
4. 4
   Temperaturathe mixture was maintained
5. 5
   workup.STIRRINGunder stirring at room temperature for 12 hours
6. 6
   workup.ADDITIONThe reaction medium was poured into ice-cold water
7. 7
   Extracciónextracted with ethyl ether
8. 8
   Otrothe organic phase decanted off
9. 9
   Secadodried over magnesium sulfate
10. 10
    Otroevaporated
11. 11
    OtroThe residue obtained
12. 12
    Otrowas chromatographed on a silica column
13. 13
    Lavadoeluted with a mixture of hexane and dichloromethane (60/40)
14. 14
    OtroAfter evaporation of the solvents, 6.35 g (74%) of the expected ester of melting point 107°-108° C.
15. 15
    Otrowere recovered

Procedimiento

A solution of 9.5 g (30 mmol) of 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-bromoanthracene was added dropwise to a suspension of 724 mg (30 mmol) of magnesium in 10 ml of THF. Once the addition was completed, the mixture was heated at reflux for one hour. At room temperature 4.1 g (30 mmol) of anhydrous zinc chloride were added and the mixture was stirred for one hour. 5.2 g (22 mmol) of ethyl 2-bromo-4-thiophenecarboxylate and 120 mg (0.22 mmol) of the complex NiCl2 /DPPE were then added successively and the mixture was maintained under stirring at room temperature for 12 hours. The reaction medium was poured into ice-cold water, extracted with ethyl ether, the organic phase decanted off, dried over magnesium sulfate and evaporated. The residue obtained was chromatographed on a silica column eluted with a mixture of hexane and dichloromethane (60/40). After evaporation of the solvents, 6.35 g (74%) of the expected ester of melting point 107°-108° C. were recovered.

Fuente