Reacción #172530

Ecuación de reacción

trimethylborate

Diisopropylamine

n-BuLi

neopentyl glycol

3-hexylthiophene

→

oil

Rendimiento 79.0%

2-(4-hexylthiophen-2-yl)-5,5-dimethyl-1,3,2-dioxaborinane

Rendimiento 79.0%

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added
2. 2
   Temperaturait was cooled down to −78° C.
3. 3
   workup.STIRRINGAfter stirring at −78° C. for 1 h the reaction
4. 4
   Temperaturawas let warm up to room temperature
5. 5
   workup.STIRRINGthe mixture was stirred for 1 h
6. 6
   TemperaturaThen, the reaction was cooled down to −78° C.
7. 7
   workup.WAITAfter 10 min
8. 8
   Temperaturathe reaction was warmed up to room temperature
9. 9
   workup.STIRRINGstirred overnight
10. 10
    OtroQuenching with 10% HCl/H2O (40 ml)
11. 11
    Extracciónthe aqueous layer was extracted with ether
12. 12
    LavadoThe ether phase was washed with water, brine
13. 13
    Secadodried over magnesium sulfate
14. 14
    Otrothe solvent was removed under vacuum
15. 15
    workup.ADDITION250 ml toluene were added to the remaining oil
16. 16
    OtroThe mixture was sparged with argon
17. 17
    Temperaturaheated up to 100° C
18. 18
    workup.WAITAfter 24 h
19. 19
    Otrothe solvent was removed under reduced pressure
20. 20
    workup.ADDITIONHexanes were added to the remaining residue
21. 21
    Otrothe hexanes phase was purified by column chromatography (99:1 to 97:3 hexanes:acetone)

Procedimiento

Diisopropylamine (7 ml, 50 mmol) was dissolved in dry THF (200 ml). The mixture was cooled down to 0° C., at which point n-BuLi (31 ml 1.6 M, 50 mmol) was added. After stirring the mixture at 0° C. for 30 min, it was cooled down to −78° C. and 3-hexylthiophene (8.1 ml, 45 mmol) was added dropwise. After stirring at −78° C. for 1 h the reaction was let warm up to room temperature, and the mixture was stirred for 1 h. Then, the reaction was cooled down to −78° C., and trimethylborate (15 ml, 134 mmol) was added. After 10 min, the reaction was warmed up to room temperature, and stirred overnight. Quenching with 10% HCl/H2O (40 ml) followed, and the aqueous layer was extracted with ether. The ether phase was washed with water, brine, dried over magnesium sulfate and the solvent was removed under vacuum. 250 ml toluene were added to the remaining oil, followed by neopentyl glycol (7.02 g, 67.4 mmol). The mixture was sparged with argon, and heated up to 100° C. After 24 h, the solvent was removed under reduced pressure. Hexanes were added to the remaining residue, and the hexanes phase was purified by column chromatography (99:1 to 97:3 hexanes:acetone). The product was obtained as a colorless oil (9.9 g, 79% yield). 1H-NMR (ppm, CDCl3): 0.85 (3H, t, J=6.24 Hz), 1.00 (6H, s), 1.22-1.33 (6H, m), 1.59 (2H, m), 2.59 (2H, t, J=7.76 Hz), 3.73 (4H, s), 7.13 (1H, s), 7.38 (1H, s); 13C-NMR (ppm, CDCl3), 14.1, 21.9, 22.6, 29.0, 30.1, 30.6, 31.7, 32.0, 72.4, 122.9, 126.5, 137.0, 144.5; ESI-MS (m/z) found: 218.1742 [M+H], calculated: 218.1753.

Fuente