反应 #45442

反应方程式

2-isopropoxy-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane

5-bromo-2-methyl-1H-indole

potassium hydride

t-butyl lithium

→

desired product

收率 63.2%

2-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole

收率 63.2%

溶剂

THF

THF

反应条件

后处理

1. 1
   workup.WAITAfter fifteen minutes at 0° C.
2. 2
   温度while maintaining the temperature below −55° C
3. 3
   温度the solution was cooled to −78° C.
4. 4
   温度to warm to room temperature
5. 5
   其他quenched with saturated aqueous ammonium chloride
6. 6
   workup.ADDITIONThe solution was diluted with ethyl acetate
7. 7
   过滤filtered
8. 8
   其他to remove inorganic material
9. 9
   萃取The filtrate was extracted with ethyl acetate
10. 10
    洗涤The combined organics were washed with brine
11. 11
    干燥dried (MgSO4)
12. 12
    浓缩concentrated
13. 13
    其他The concentrate was purified by flash chromatography on silica gel using 10% ethyl acetate/hexanes

实验过程

A solution of 5-bromo-2-methyl-1H-indole (5.04 g, 24 mmol) in THF (25 mL) was added dropwise to a suspension of potassium hydride (3.2 g, 24 mmol) in THF at 0° C. After fifteen minutes at 0° C., the solution was cooled to −78° C. and a t-butyl lithium solution (1.7 M in pentane, 28.2 mL, 48 mmol) was added dropwise via syringe while maintaining the temperature below −55° C. After an additional 15 minutes, the solution was cooled to −78° C. and treated with a 2-isopropoxy-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (9.8 mL, 48 mmol) dropwise via syringe. The solution was stirred at −78° C. for 1.5 hours, allowed to warm to room temperature and quenched with saturated aqueous ammonium chloride. The solution was diluted with ethyl acetate and filtered to remove inorganic material. The filtrate was extracted with ethyl acetate. The combined organics were washed with brine, dried (MgSO4) and concentrated. The concentrate was purified by flash chromatography on silica gel using 10% ethyl acetate/hexanes to give 3.9 g (63% yield) of the desired product. MS (ESI(+)) m/e 258 (M+H)+.

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