Reaction #56722

Reaction equation

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

Solvents

THF

THF

THF

THF

Conditions

Workup

1. 1
   TemperatureThe mixture was heated
2. 2
   workup.ADDITIONadded dropwise
3. 3
   Temperaturecooled to −5° C
4. 4
   Otherthe temperature below 0° C
5. 5
   workup.STIRRINGThe resulting mixture was stirred for 20 min
6. 6
   Otherthe temperature below 0° C
7. 7
   Otherwas allowed to slowly reach ambient temperature overnight
8. 8
   OtherThe reaction mixture was quenched with ammonium hydroxide and water
9. 9
   workup.ADDITIONThe mixture was diluted with EtOAc
10. 10
    Extractionextracted with 3×20 mL EtOAc
11. 11
    WashThe organics were washed with brine
12. 12
    Dryingdried (MgSO4)
13. 13
    Filtrationfiltered
14. 14
    Concentrationconcentrated
15. 15
    OtherThe residual oil was purified via silica gel chromatography (90/10 Hexane/EtOAc)

Procedure

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.

Source