Bromobenzene → 4-Phenyl-1H-indole

HRID 982975Notes

Reaction equation

HRID 982975 reaction equation
CC1(C)C(C)(C)OB([C:9]2[CH:17]=[CH:16][CH:15]=[C:14]3[C:10]=2[CH:11]=[CH:12][NH:13]3)O1.N1[C:27]2[CH:26]=[CH:25][CH:24]=[C:23](B([O-])[O-])[C:22]=2C=C1.BrC1C=CC=CC=1.[OH-].[Na+]>C1COCC1.[Pd]>[C:22]1([C:9]2[CH:17]=[CH:16][CH:15]=[C:14]3[C:10]=2[CH:11]=[CH:12][NH:13]3)[CH:23]=[CH:24][CH:25]=[CH:26][CH:27]=1

Participants

7

Reactant 4

HCID 7961BromobenzeneHCID 14798Sodium HydroxideHCID 113224711H-Indole-4-boronic acid, pinacol esterHCID 865876564-Indoleboronate

Product 1

HCID 158062984-Phenyl-1H-indoleYield 78%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
70 °C

Procedure

To a mixture of 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)1H-indole (pinacole 4-indoleboronate (2 g, 8.2 mmol) and 3-bromobenzene (0.87 mL, 8.3 mmol) in THF (28 mL) were added Palladium catalyst Pd(PPh3)4 (284 mg, 0.25 mmol) and the freshly prepared sodium hydroxide solution (984 mg in 9 mL of water). The system was degassed and then charged with nitrogen for three times. The mixture was stirred under nitrogen at 70° C. oil bath for 6 hours. The reaction solution was cooled to room temperature, diluted with ethyl acetate and separated from water layer. The ethyl acetate solution was washed by brine, dried over Na2SO4 and concentrated. The residue was purified on a silica gel column eluting with hexanes:EtOAc 9:1 to give 1.38 g (78%) of 4-phenyl-1H-indole as a colorless liquid.

Workup

  1. customThe system was degassed
  2. additioncharged with nitrogen for three times
  3. temperatureThe reaction solution was cooled to room temperature
  4. additiondiluted with ethyl acetate
  5. customseparated from water layer
  6. washThe ethyl acetate solution was washed by brine
  7. dry with materialdried over Na2SO4
  8. concentrationconcentrated
  9. customThe residue was purified on a silica gel column
  10. washeluting with hexanes:EtOAc 9:1

Sources & evidence

ORD record
ord-7868c3ce25084aeaacfcf29dbb412fc8
Source dataset
uspto-grants-2005_03
Patent number
US06861418B2

Reaction notes

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