Acetic Acid → 2-Benzyl-1,2,3,4-tetrahydronaphthalen-1-one

HRID 1532398Notes

Reaction equation

HRID 1532398 reaction equation
F[C:2]1[CH:9]=[CH:8][C:5]([CH2:6]Br)=[CH:4][CH:3]=1.C(Cl)(Cl)Cl.[C:14]([OH:17])(=O)[CH3:15].O.[C:19](#N)[CH3:20]>>[CH2:6]([CH:20]1[CH2:19][CH2:5][C:4]2[C:15](=[CH:8][CH:9]=[CH:2][CH:3]=2)[C:14]1=[O:17])[C:5]1[CH:8]=[CH:9][CH:2]=[CH:3][CH:4]=1

Participants

6

Reactant 5

HCID 176Acetic AcidHCID 962WaterHCID 6212Chloroform2×HCID 6342AcetonitrileHCID 680214-Fluorobenzyl bromide

Product 1

HCID 5635332-Benzyl-1,2,3,4-tetrahydronaphthalen-1-one

Procedure

4-Fluorobenzyl bromide (20.7 g, 109 mmol) was added to a solution of the enamine in acetonitrile (200 mL) which had been dried over 4A molecular sieves. This mixture was heated at reflux under nitrogen for 3 days. After cooling, the reaction mixture was concentrated in vacuo to provide a brown solid. Chloroform (25 mL), glacial acetic acid (50 mL), and water (200 mL) were added to this material and the resulting mixture was stirred at ambient temperature for 20 h. Additional chloroform was added to the reaction mixture, and the layers were separated. The organic layer was washed with water, dried (Na2SO4), and concentrated to give 24.2 g of the corresponding -benzyl--tetralone as a dark brown oil. This material was purified on a flash silica gel column (25% hexanes-chloroform) to provide 17.9 g of a red oil which was purified further on a flash silica gel column (1:1 hexanes-chloroform) to provide 12.1 g (70%) of desired product, 1-(4-fluorobenzyl)--tetralone, as a yellow oil. MS (CI-CH4), m/z 255 (MH+). 1H NMR (CDCl3) 2.38-2.56 (m, 3H), 2.76-2.86 (m 1H), 3.21 (AB octet, J=15.5, 6.8 Hz, 2H), 3.70 (t, J=6.2 Hz, 1 H), 6.75-6.85 (m, 4H), 6.93 (dd, J=7.5, 2.8 Hz, 1H), 7.09-7.22 (m, 3H).

Workup

  1. dry with materialhad been dried over 4A molecular sieves
  2. temperatureThis mixture was heated
  3. temperatureat reflux under nitrogen for 3 days
  4. temperatureAfter cooling
  5. concentrationthe reaction mixture was concentrated in vacuo
  6. customto provide a brown solid
  7. customthe layers were separated
  8. washThe organic layer was washed with water
  9. dry with materialdried (Na2SO4)
  10. concentrationconcentrated

Sources & evidence

ORD record
ord-8a20ca1a500745f8847494b96d61b53d
Source dataset
uspto-grants-2001_03
Patent number
US06201025B1

Reaction notes

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