Cesium carbonate → Benzoic acid, 2-bromo-4-ethenyl-, ethyl ester

HRID 1502943Notes

Reaction equation

HRID 1502943 reaction equation
[Br:1][C:2]1[CH:12]=[C:11](I)[CH:10]=[CH:9][C:3]=1[C:4]([O:6][CH2:7][CH3:8])=[O:5].[CH:14]([B-](F)(F)F)=[CH2:15].[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>[Br:1][C:2]1[CH:12]=[C:11]([CH:14]=[CH2:15])[CH:10]=[CH:9][C:3]=1[C:4]([O:6][CH2:7][CH3:8])=[O:5]

Participants

7

Reactant 4

HCID 10796Cesium carbonateHCID 11776TriphenylphosphineHCID 23679353Potassium vinyltrifluoroborateHCID 71138507Benzoic acid, 2-bromo-4-iodo-, ethyl ester

Product 1

HCID 86675122Benzoic acid, 2-bromo-4-ethenyl-, ethyl ester

Reagents, catalysts & solvents 2

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

Procedure

To a stirred solution of ethyl 2-bromo-4-iodobenzoate (5 g, 14.3 mmol) in THF/water (100 mL, 9:1) was added potassium vinyltrifluoroborate (1.89 g, 14.3 mmol), Cs2CO3 (18.27 g, 56.07 mmol) and triphenylphosphine (0.22 g, 0.85 mmol) and the reaction mixture was degassed with argon for 20 min, then charged with PdCl2 (0.05 g, 0.28 mmol). The reaction mixture was heated to reflux for 16 h. The reaction mixture was cooled to ambient temperature and filtered through a celite bed and washed with ethyl acetate. The filtrate was again extracted with ethyl acetate and the combined organic layers washed with water and brine, dried over Na2SO4 and concentrated under reduced pressure to afford crude compound. The crude compound was purified by column chromatography (SiO2, 100-200 mesh; eluting with 2% ethyl acetate/petroleum ether) to afford the title compound as a light brown gummy material (2 g, 56%): 1H NMR (400 MHz, CDCl3) δ 7.78 (d, J=8.4 Hz, 1H), 7.71 (d, J=1.2 Hz, 1H), 7.51 (d, J=8.4 Hz, 1H), 6.69 (dd, J=17.6, 10.8 Hz, 1H), 5.86 (d, J=17.6 Hz, 1H), 5.42 (d, J=11.2 Hz, 1H), 4.42 (q, J=7.2 Hz, 2H), 1.43 (t, J=3.6 Hz, 3H); ESIMS m/z 255.18 ([M+H]+); IR (thin film) 1729 cm−1.

Workup

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

Sources & evidence

ORD record
ord-700ee1155aad4460aa4371007a020259
Source dataset
uspto-grants-2015_12
Patent number
US09211281B2

Reaction notes

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