2,5-Difluorobenzaldehyde → 2,5-Difluorostyrene

HRID 2362409Notes

Reaction equation

HRID 2362409 reaction equation
[Li][CH2:2]CCC.[F:6][C:7]1[CH:14]=[CH:13][C:12]([F:15])=[CH:11][C:8]=1[CH:9]=O>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.O1CCCC1>[F:6][C:7]1[CH:14]=[CH:13][C:12]([F:15])=[CH:11][C:8]=1[CH:9]=[CH2:2]

Participants

5

Reactant 2

HCID 1376632,5-DifluorobenzaldehydeHCID 178418339Butyllithium

Product 1

HCID 218718902,5-Difluorostyrene

Reagents, catalysts & solvents 2

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
0 °C

Procedure

To a suspension of methyltriphenylphosphonium bromide (26.4 g, 73.9 mmol) in tetrahydrofuran (350 mL) at 0° C. was added nBuLi (2.5M in hexane, 29.6 mL, 73.9 mmol). After addition was complete, the reaction was stirred at 0° C. for 10 min. To this was added 2,5-difluorobenzaldehyde (5.35 mL, 49.3 mmol). The ice bath was removed, and stirring continued for 1 h. The reaction was quenched by addition of saturated ammonium chloride. The reaction was poured into ether, washed with water (3×), then brine, dried over magnesium sulfate, and concentrated. Column chromatography (2.5% EtOAc/Hex) gave 2.1 g (30%) as a colorless oil. 1H NMR (CDCl3) Shift: 7.20 (ddd, J=9.2, 5.9, 3.2 Hz, 1H), 7.02 (td, J=9.3, 4.6 Hz, 1H), 6.90-6.97 (m, 1H), 6.86 (dd, J=17.7, 11.3 Hz, 1H), 5.84 (d, J=17.7 Hz, 1H), 5.45 (d, J=11.0 Hz, 1H). 13C NMR (CDCl3) Shift: 158.6, 156.3, 128.6, 126.8, 117.6, 116.8, 115.6, 113.0. 19F NMR (CDCl3) Shift: −120.17-119.46 (m, 1F), −125.20 (d, J=17.3 Hz, 1F).

Workup

  1. additionAfter addition
  2. customThe ice bath was removed
  3. stirringstirring
  4. waitcontinued for 1 h
  5. customThe reaction was quenched by addition of saturated ammonium chloride
  6. additionThe reaction was poured into ether
  7. washwashed with water (3×)
  8. dry with materialbrine, dried over magnesium sulfate
  9. concentrationconcentrated
  10. customColumn chromatography (2.5% EtOAc/Hex) gave 2.1 g (30%) as a colorless oil

Sources & evidence

ORD record
ord-8cbeee8bae6a4e9488e84d7920d2fda7
Source dataset
uspto-grants-2014_04
Patent number
US08691821B2

Reaction notes

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