Réaction #61317

Équation de réaction

HCl

MgBr2

allyl bromide

BuLi

1-bromo-2-(dimethoxymethyl)benzene

→

2-allylbenzaldehyde

Rendement 34.0%

Solvants

Et2O

Et2O

Et2O

Conditions de réaction

Traitement

1. 1
   Températureto 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
   Températurewhile warming up to rt
5. 5
   Lavagewashed with aq. 1M HCl (1×)
6. 6
   SéchageExtracts were dried over MgSO4
7. 7
   Filtrationfiltered
8. 8
   Autrethe 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
    Autrethe solvents were partially removed under reduced pressure
13. 13
    workup.ADDITIONThe residue was diluted with Et2O
14. 14
    Lavagewashed with aq. 1M HCl (1×), and aq. sat. NaHCO3 (1×)
15. 15
    Séchageextracts were dried over MgSO4
16. 16
    Filtrationfiltered
17. 17
    Autrethe solvents were removed under reduced pressure
18. 18
    AutrePurification of the residue by FC (Et2O/petroleum ether 1:49→24:1)

Mode opératoire

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.

Source