P-Chloroacetophenone → 4-Chloro-alpha-methylstyrene

HRID 543868

Reaction equation

HRID 543868 reaction equation
[Br-].[C:2]1([C:8]([PH3+])([C:15]2C=CC=CC=2)[C:9]2C=CC=CC=2)[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C([Li])CCC.CC(C1C=CC([Cl:36])=CC=1)=O>O1CCCC1.CCCCCC>[Cl:36][C:5]1[CH:6]=[CH:7][C:2]([C:8]([CH3:15])=[CH2:9])=[CH:3][CH:4]=1

Participants

6

Reactant 3

HCID 7467P-ChloroacetophenoneHCID 21951224Triphenylmethyl phosphonium bromideHCID 178418339Butyllithium

Product 1

HCID 743814-Chloro-alpha-methylstyreneYield 54.2%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 8058HexaneSolvent

Conditions

Temperature
-10 °C

Procedure

To a slurry of triphenylmethylphosphonium bromide (71.4 grams (g), 200 millimole (mmole)) in 500 milliliters (ml) dry tetrahydrofuran (THF) (distilled from sodium/benzophenone), were slowly added dropwise 129 ml (200 mmole) 1.55 molar (M) n-butyllithium in hexane. The reaction mixture was stirred for 30 minutes at -10° C. whereafter a solution of 30.92 g (200 mmol) 4-chloroacetophenone in 100 ml dry THF was slowly added dropwise. The reaction mixture was then stirred for one hour at -10° C., slowly warmed to ambient temperature (about 23° C.) and stirring continued overnight. The mixture was thereafter filtered and the solvent removed by distillation at atmospheric pressure. Distillation, using a water aspirator, yielded 16.5 g (54.2% yield) of p-chloro-α-methylstyrene, boiling point (bp) 82°-86° C.

Workup

  1. additionwas slowly added dropwise
  2. temperatureslowly warmed to ambient temperature (about 23° C.)
  3. stirringstirring continued overnight
  4. filtrationThe mixture was thereafter filtered
  5. customthe solvent removed by distillation at atmospheric pressure
  6. distillationDistillation

Sources & evidence

ORD record
ord-3c4c11c1c74e40fd8a1f3ba7fee0199e
Source dataset
uspto-grants-1984_05
Patent number
US04447542

Linked notes

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