反応 #56722

反応方程式

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

溶媒

THF

THF

THF

THF

反応条件

後処理

1. 1
   温度The mixture was heated
2. 2
   workup.ADDITIONadded dropwise
3. 3
   温度cooled to −5° C
4. 4
   その他the temperature below 0° C
5. 5
   workup.STIRRINGThe resulting mixture was stirred for 20 min
6. 6
   その他the temperature below 0° C
7. 7
   その他was allowed to slowly reach ambient temperature overnight
8. 8
   その他The reaction mixture was quenched with ammonium hydroxide and water
9. 9
   workup.ADDITIONThe mixture was diluted with EtOAc
10. 10
    抽出extracted with 3×20 mL EtOAc
11. 11
    洗浄The organics were washed with brine
12. 12
    乾燥dried (MgSO4)
13. 13
    ろ過filtered
14. 14
    濃縮concentrated
15. 15
    その他The residual oil was purified via silica gel chromatography (90/10 Hexane/EtOAc)

実験手順

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.

出典