Reaktion #61317

Reaktionsgleichung

HCl

MgBr2

allyl bromide

BuLi

1-bromo-2-(dimethoxymethyl)benzene

→

2-allylbenzaldehyde

Ausbeute 34.0%

Lösungsmittel

Et2O

Et2O

Et2O

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto warm up to 0° C. over 15 min
2. 2
   workup.STIRRINGThe mixture was stirred at 0° C. for 5 min
3. 3
   workup.STIRRINGThe mixture was stirred overnight
4. 4
   Temperaturwhile warming up to rt
5. 5
   Waschenwashed with aq. 1M HCl (1×)
6. 6
   TrocknenExtracts were dried over MgSO4
7. 7
   Filtrationfiltered
8. 8
   Sonstigethe solvents were removed under reduced pressure
9. 9
   workup.DISSOLUTIONThe residue was dissolved in acetone (20 mL)
10. 10
    workup.ADDITIONwater (10 mL), and TosOH (cat. amount) was added
11. 11
    workup.STIRRINGThe mixture was stirred for 5 h at rt
12. 12
    Sonstigethe solvents were partially removed under reduced pressure
13. 13
    workup.ADDITIONThe residue was diluted with Et2O
14. 14
    Waschenwashed with aq. 1M HCl (1×), and aq. sat. NaHCO3 (1×)
15. 15
    Trocknenextracts were dried over MgSO4
16. 16
    Filtrationfiltered
17. 17
    Sonstigethe solvents were removed under reduced pressure
18. 18
    SonstigePurification of the residue by FC (Et2O/petroleum ether 1:49→24:1)

Vorschrift

BuLi (1.55 M in hexane, 14.7 mL, 22.7 mmol) was added to a sol. of 1-bromo-2-(dimethoxymethyl)benzene (5.00 g, 21.6 mmol) in Et2O (50 mL). The mixture was stirred for 30 min at −78 ° C. and MgBr2.Et2O (5.87 g, 22.7 mmol) was added. The mixture was allowed to warm up to 0° C. over 15 min and CuI (420 mg, 2.16 mmol) was added. The mixture was stirred at 0° C. for 5 min and allyl bromide (1.92 mL, 22.7 mmol) was added. The mixture was stirred overnight while warming up to rt. Aq. 1M HCl (1 mL) was added and the mixture was diluted with Et2O, and washed with aq. 1M HCl (1×). The org. Extracts were dried over MgSO4, filtered, and the solvents were removed under reduced pressure. The residue was dissolved in acetone (20 mL) and water (10 mL), and TosOH (cat. amount) was added. The mixture was stirred for 5 h at rt, and the solvents were partially removed under reduced pressure. The residue was diluted with Et2O, and washed with aq. 1M HCl (1×), and aq. sat. NaHCO3 (1×). The org. extracts were dried over MgSO4, filtered, and the solvents were removed under reduced pressure. Purification of the residue by FC (Et2O/petroleum ether 1:49→24:1) yielded 2-allylbenzaldehyde (1.06 g, 34%). This compound was transformed into the title compound following typical procedure J with cyclopropylamine.

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