Reaction #1477

Reaction equation

t-butyl magnesium chloride

MeOH

p-tolylsulfonic acid

7-bromo-3,4-dihydro-4,4-dimethylnaphthalen-1(2H)-one

Compound G

7-bromo-3,4-dihydro-4,4-dimethylnaphthalen-1(2H)-one

→

title compound

7-Bromo-1-(1,1-dimethylethyl)-3,4-dihydro-4,4-dimethylnaphthalene

Solvents

THF

Conditions

Workup

1. 1
   OtherThe reaction was quenched at 0° C. with saturated ammonium chloride solution (20 ml)
2. 2
   Extractionextracted with EtOAc (2×50 ml)
3. 3
   ExtractionThe combined extract
4. 4
   Washwas washed with water (20 ml), brine (20 ml)
5. 5
   Dryingdried over MgSO4
6. 6
   OtherThe solvent was evaporated under reduced pressure
7. 7
   Otherto afford a yellow oil
8. 8
   OtherThe resultant reaction solution
9. 9
   Temperaturewas heated in an oil bath (60° C.) for 3 h
10. 10
    TemperatureThe reaction was cooled
11. 11
    Otherquenched with water (20 ml)
12. 12
    Extractionextracted with EtOAc (2×50 ml)
13. 13
    ExtractionThe combined extract
14. 14
    Washwas washed with saturated NaHCO3 (20 ml), water (20 ml), brine (20 ml)
15. 15
    Dryingdried over MgSO4
16. 16
    ConcentrationThe solvent was concentrated in vacuo

Procedure

In a flame dried round bottom flask 7-bromo-3,4-dihydro-4,4-dimethylnaphthalen-1(2H)-one (Compound G, 2.0 g, 7.93 mmol) was dissolved in anhydrous THF (50 ml) and 3,4,5,6,-tetrahydro-2(H)-pyrimidinone (DMPU) (11.5 ml, 95.16 mmol) was added, under argon atmosphere. The reaction was then cooled to -20° C. and a solution of t-butyl magnesium chloride (16 ml, 31.7 mmol) (2M in Et2O) was added dropwise and stirred at -20° C. for 2 h and at ambient temperature for 1 h, under argon atmosphere. The reaction was quenched at 0° C. with saturated ammonium chloride solution (20 ml) and extracted with EtOAc (2×50 ml). The combined extract was washed with water (20 ml), brine (20 ml) and dried over MgSO4. The solvent was evaporated under reduced pressure to afford a yellow oil. To this yellow oil were added MeOH (50 ml) and p-tolylsulfonic acid (100 mg). The resultant reaction solution was heated in an oil bath (60° C.) for 3 h. The reaction was cooled and quenched with water (20 ml), extracted with EtOAc (2×50 ml). The combined extract was washed with saturated NaHCO3 (20 ml), water (20 ml), brine (20 ml), and dried over MgSO4. The solvent was concentrated in vacuo and the title compound was obtained as a colorless oil after purification by flash chromatography (silica, hexane).

Source