Cesium carbonate → 5-Ethenyl-1H-indole

HRID 1502843Notes

Reaction equation

HRID 1502843 reaction equation
Br[C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][CH:6]=[CH:5]2.[CH:11]([B-](F)(F)F)=[CH2:12].[K+].C([O-])([O-])=O.[Cs+].[Cs+].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>C1COCC1.O.Cl[Pd]Cl>[CH:11]([C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][CH:6]=[CH:5]2)=[CH2:12]

Participants

7

Reactant 4

HCID 10796Cesium carbonateHCID 11776TriphenylphosphineHCID 249055-BromoindoleHCID 23679353Potassium vinyltrifluoroborate

Product 1

HCID 126103725-Ethenyl-1H-indole

Reagents, catalysts & solvents 2

HCID 24290Palladium ChlorideCatalystHCID 21881883Oxolane--water (1/1)Solvent

Procedure

A mixture of 5-bromo-1H-indole (2.5 g, 12.82 mmol), potassium vinyltrifluoroborate (2.57 g, 19.2 mmol), Cs2CO3 (12.53 g, 38.46 mmol) and triphenylphosphine (201 mg, 0.769 mmol) in THF/water (9:1, 75 ml) was degassed with argon for 20 min, then charged with PdCl2 (45.3 mg, 0.256 mmol). The reaction mixture was heated to reflux for 16 h, then cooled to ambient temperature, filtered through celite bed and washed with ethyl acetate. The filtrate was again extracted with ethyl acetate, and the combined organic layer washed with water and brine, dried over Na2SO4 and concentrated under reduced pressure to afford the crude compound. The crude compound was purified by column chromatography (SiO2, 100-200 mesh; 2% ethyl acetate/petroleum ether) to afford the title compound as a light brown gummy material (1.5 g, 83%): 1H NMR (400 MHz, CDCl3) δ 8.20 (br, 1H), 7.68 (s, 1H), 7.45 (s, 2H), 7.21 (m, 1H), 6.90 (dd, J=16.0, 10.8 Hz, 1H), 6.55 (m, 1H), 5.75 (d, J=10.5 Hz, 1H), 5.21 (d, J=10.5 Hz, 1H); ESIMS m/z 142.05 ([M−H]−).

Workup

  1. customwas degassed with argon for 20 min
  2. temperatureThe reaction mixture was heated
  3. temperatureto reflux for 16 h
  4. filtrationfiltered through celite bed
  5. washwashed with ethyl acetate
  6. extractionThe filtrate was again extracted with ethyl acetate
  7. washthe combined organic layer washed with water and brine
  8. dry with materialdried over Na2SO4
  9. concentrationconcentrated under reduced pressure
  10. customto afford the crude compound
  11. customThe crude compound was purified by column chromatography (SiO2, 100-200 mesh; 2% ethyl acetate/petroleum ether)

Sources & evidence

ORD record
ord-52dded264be44795b5a539b6dd57f820
Source dataset
uspto-grants-2015_12
Patent number
US09211280B2

Reaction notes

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