Reaktion #56722

Reaktionsgleichung

LiCl

(R)-3-bromo-2-methylpropanol

Magnesium

iodine

1-bromo-3-methyl butane

1-bromo-3-methyl butane

→

(R)-2,6-dimethyl heptan-1-ol

Lösungsmittel

THF

THF

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was heated
2. 2
   workup.ADDITIONadded dropwise
3. 3
   Temperaturcooled to −5° C
4. 4
   Sonstigethe temperature below 0° C
5. 5
   workup.STIRRINGThe resulting mixture was stirred for 20 min
6. 6
   Sonstigethe temperature below 0° C
7. 7
   Sonstigewas allowed to slowly reach ambient temperature overnight
8. 8
   SonstigeThe reaction mixture was quenched with ammonium hydroxide and water
9. 9
   workup.ADDITIONThe mixture was diluted with EtOAc
10. 10
    Extraktionextracted with 3×20 mL EtOAc
11. 11
    WaschenThe organics were washed with brine
12. 12
    Trocknendried (MgSO4)
13. 13
    Filtrationfiltered
14. 14
    Einengenconcentrated
15. 15
    SonstigeThe residual oil was purified via silica gel chromatography (90/10 Hexane/EtOAc)

Vorschrift

Magnesium turnings (2.04 g, 84 mmol) and a crystal of iodine were suspended in 5 mL THF for the addition of 1-bromo-3-methyl butane (0.3 mL, neat). The mixture was heated to start the Grignard formation. The remaining 1-bromo-3-methyl butane (8.63 mL, 72 mmol) was diluted in THF (60 mL) and added dropwise. The mixture was stirred at ambient temperature for 2 hours and cooled to −5° C. A solution of copper chloride (1.21 g, 9 mmol) and LiCl (0.76 g, 18 mmol) in THF (50 mL) was added dropwise keeping the temperature below 0° C. The resulting mixture was stirred for 20 min, and (R)-3-bromo-2-methylpropanol in THF (20 mL) was added dropwise while keeping the temperature below 0° C. The mixture was allowed to slowly reach ambient temperature overnight. The reaction mixture was quenched with ammonium hydroxide and water. The mixture was diluted with EtOAc and extracted with 3×20 mL EtOAc. The organics were washed with brine, dried (MgSO4), filtered and concentrated. The residual oil was purified via silica gel chromatography (90/10 Hexane/EtOAc) to give 2.67 g (R)-2,6-dimethyl heptan-1-ol.

Quelle