Reaction #1462445

Reaction equation

3,4-dihydro-4,4-dimethyl-7-bromo-1(2H)-naphthalenone

Compound A

3,4-dihydro-4,4-dimethyl-7-bromo-1(2H)-naphthalenone

2-methylthiophene

n-BuLi

→

title compound

Yield 62.3%

1-(5-Methyl-thien-2-yl)3,4-dihydro-4,4-dimethyl-7-bromo-naphthalene

Yield 62.3%

Solvents

THF

ether ethylacetate

THF

Conditions

Workup

1. 1
   Othertransferred to a cold (−78° C.) flask
2. 2
   Washwashed with water (10 mL), brine (10 mL)
3. 3
   Dryingdried with MgSO4
4. 4
   Otherthe solvent was removed by evaporation
5. 5
   workup.DISSOLUTIONThe crude material was dissolved in dichloroethane (20 mL)
6. 6
   workup.ADDITIONpTSA (40 mg) was added
7. 7
   workup.STIRRINGThe mixture was stirred at ambient temperature for 16 hours and at 50° C. for 4 hours
8. 8
   workup.ADDITIONThe reaction mixture was diluted with ether (150 mL)
9. 9
   Washwashed with aqueous 10% NaHCO3 (10 mL), brine (10 mL)
10. 10
    Dryingdried with MgSO4
11. 11
    OtherPurification by chromatography on silica gel

Procedure

To a cold (−78° C.) solution of 2-methylthiophene (800 mg, 8.1 mmol) in THF (10 mL) was added n-BuLi (1.6M solution in hexane, 5 mL). The mixture was stirred for 1.5 hours and transferred to a cold (−78° C.) flask containing 3,4-dihydro-4,4-dimethyl-7-bromo-1(2H)-naphthalenone (Compound A, 1.63 g, 6.5 mmol), in THF (15 mL). The mixture was gradually warmed to 0° C. The reaction mixture was diluted with ether:ethylacetate (1:1, 80 mL), washed with water (10 mL), brine (10 mL). dried with MgSO4 and the solvent was removed by evaporation. The crude material was dissolved in dichloroethane (20 mL) and pTSA (40 mg) was added. The mixture was stirred at ambient temperature for 16 hours and at 50° C. for 4 hours. . The reaction mixture was diluted with ether (150 mL), washed with aqueous 10% NaHCO3 (10 mL), brine (10 mL) and dried with MgSO4. Purification by chromatography on silica gel gave 1.35 g of the title compound as a white solid.

Source