Reaction #1221

Reaction equation

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

Solvents

THF

Conditions

Workup

1. 1
   workup.ADDITIONOnce the addition
2. 2
   Temperaturethe mixture was heated
3. 3
   Temperatureat reflux for one hour
4. 4
   Temperaturethe 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
   Extractionextracted with ethyl ether
8. 8
   Otherthe organic phase decanted off
9. 9
   Dryingdried over magnesium sulfate
10. 10
    Otherevaporated
11. 11
    OtherThe residue obtained
12. 12
    Otherwas chromatographed on a silica column
13. 13
    Washeluted with a mixture of hexane and dichloromethane (60/40)
14. 14
    OtherAfter evaporation of the solvents, 6.35 g (74%) of the expected ester of melting point 107°-108° C.
15. 15
    Otherwere recovered

Procedure

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.

Source