Reaction #1885016

Reaction equation

trimethyl borate

tetrahydrofuran

9-(2′-bromophenyl)-9H-carbazole

hexane

n-butyllithium

hydrochloric acid

→

powdery white solid

Yield 55.0%

4′-(9H-carbazol-9-yl)biphenyl-2-boronic acid

Yield 55.0%

Conditions

Workup

1. 1
   OtherInto 300 mL three-neck flask were put
2. 2
   OtherAfter the solution was degassed under low pressure
3. 3
   workup.STIRRINGthe solution was stirred at −78° C. for 2 hours
4. 4
   workup.STIRRINGthe mixture was stirred −78° C. for 1 hour
5. 5
   workup.STIRRINGwas stirred for about 24 hours while the temperature of the mixture
6. 6
   Otherwas being gradually brought back to room temperature
7. 7
   workup.STIRRINGthe solution was stirred for 30 minutes at a room temperature
8. 8
   workup.ADDITIONAfter the stirring, to this mixture was added
9. 9
   Extractionethyl acetate, and extraction with ethyl acetate
10. 10
    ExtractionAfter the extraction
11. 11
    Washwashed with brine
12. 12
    workup.ADDITIONAfter the washing, magnesium sulfate was added into the organic layer
13. 13
    Otherto dry the organic layer
14. 14
    FiltrationAfter the drying, the mixture was subjected to suction filtration
15. 15
    Otherto give a filtrate
16. 16
    ConcentrationThe obtained filtrate was concentrated
17. 17
    Otherrecrystallized with a mixture solvent of chloroform and hexane

Procedure

Into 300 mL three-neck flask were put a mixed solution of 6.2 g (16 mmol) of 9-(2′-bromophenyl)-9H-carbazole and 100 mL of tetrahydrofuran (THF). After the solution was degassed under low pressure, the atmosphere in the flask was substituted by nitrogen. The solution was stirred at −78° C. for 20 minutes. After the stirring, 12 mL (19 mmol) of hexane solution of 1.55 mol/L of n-butyllithium was dripped with a syringe, and the solution was stirred at −78° C. for 2 hours. After the stirring, 4.0 mL of trimethyl borate was added and the mixture was stirred −78° C. for 1 hour, and then was stirred for about 24 hours while the temperature of the mixture was being gradually brought back to room temperature. After the stirring, to this solution was added 50 mL of 1M dilute hydrochloric acid, and the solution was stirred for 30 minutes at a room temperature. After the stirring, to this mixture was added ethyl acetate, and extraction with ethyl acetate was performed. After the extraction, the extracted solution was combined with the organic layer and washed with brine. After the washing, magnesium sulfate was added into the organic layer to dry the organic layer. After the drying, the mixture was subjected to suction filtration to give a filtrate. The obtained filtrate was concentrated and recrystallized with a mixture solvent of chloroform and hexane to give 3.2 g of a powdery white solid in a yield of 55%.

Source