Reaktion #1938311

Reaktionsgleichung

THF

1,2-dibromo-4-fluoro-3-iodobenzene

Ethynyltrimethylsilane

→

((2,3-dibromo-6-fluorophenyl)ethynyl)trimethylsilane

Ausbeute 79.4%

Lösungsmittel

EtOAc

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigesealed with a rubber septum
2. 2
   Sonstigethe mixture was degassed 10 min
3. 3
   Sonstigeby sparging with N2
4. 4
   Sonstigewhile immersed in an ultrasonic bath
5. 5
   Temperaturthe mixture was cooled
6. 6
   Filtrationfiltered through a pad of Celite
7. 7
   WaschenThe filtrate was washed (satd NH4Cl×2, water, brine)
8. 8
   Trocknendried over Na2SO4
9. 9
   Einengenconcentrated in vacuo
10. 10
    SonstigeThe residue was purified by low pressure liquid chromatography (silica gel, EtOAc/hexanes, gradient elution)

Vorschrift

A thick-walled glass vessel was charged with 1,2-dibromo-4-fluoro-3-iodobenzene (8.31 g, 21.88 mmol), Pd(PPh3)2Cl2 (0.768 g, 1.094 mmol), and CuI (0.292 g, 1.532 mmol) and sealed with a rubber septum. Anhyd THF (30 mL) and DIPA (30.8 mL, 219 mmol) were added via syringe and the mixture was degassed 10 min by sparging with N2 while immersed in an ultrasonic bath. Ethynyltrimethylsilane (3.40 mL, 24.07 mmol) was added via syringe and the septum was replaced with a PTFE bushing. The mixture was stirred in an oil bath at 40° C. After 40 h, the mixture was cooled, diluted with EtOAc and filtered through a pad of Celite. The filtrate was washed (satd NH4Cl×2, water, brine), dried over Na2SO4 and concentrated in vacuo. The residue was purified by low pressure liquid chromatography (silica gel, EtOAc/hexanes, gradient elution) affording ((2,3-dibromo-6-fluorophenyl)ethynyl)trimethylsilane (6.08 g, 17.37 mmol, 79% yield) as a yellow oil: 1H NMR (400 MHz, CDCl3) δ 7.53 (dd, J=8.9, 5.4 Hz, 1H), 6.95 (dd, J=8.9, 8.1 Hz, 1H), 0.29 (s, 9H); MS (GCMS EI) m/z 348 ([M]+, Br isotopes, 18%), 350 ([M]+, Br isotopes, 34%), 352 ([M]+, Br isotopes, 18%), 333 ([M-CH3]+, Br isotopes, 56%), 335 ([M-CH3]+, Br isotopes, 100%), 337 ([M-CH3]+, Br isotopes, 54%).

Quelle