3,5-Dibromobenzaldehyde → 3,5-Dibromostyrene

HRID 1822315Notes

Reaction equation

HRID 1822315 reaction equation
[CH3:1]C(C)([O-])C.[K+].[Br:7][C:8]1[CH:9]=[C:10]([CH:13]=[C:14]([Br:16])[CH:15]=1)[CH:11]=O>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C1COCC1>[Br:7][C:8]1[CH:9]=[C:10]([CH:11]=[CH2:1])[CH:13]=[C:14]([Br:16])[CH:15]=1

Participants

5

Reactant 2

HCID 6220773,5-DibromobenzaldehydeHCID 23665647Potassium tert-butoxide

Product 1

HCID 186903433,5-DibromostyreneYield 46%

Reagents, catalysts & solvents 2

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 8028TetrahydrofuranSolvent2×

Procedure

A solution of methyltriphenylphosphonium bromide (20.30 g, 56.8 mmol) in dry THF (50 mL) is cooled to 0° C. under N2 and then treated with solid potassium tert-butoxide (6.38 g, 56.8 mmol) in portions. The resultant yellow slurry is warmed to rt and stirred for 30 minutes. The mixture is cooled to −78° C., and a solution of 3,5-dibromobenzaldehyde (10.0 g, 37.9 mmol) in THF (50 mL) is added dropwise. The reaction is warmed to rt and stirred for 1 hour. The mixture is poured into ice water containing 1 N HCl (56 mL) and then extracted with Et2O. The organic layer is dried (Na2SO4), and the solvent is removed in vacuo to afford crude product that is absorbed on silica gel and purified by flash chromatography using 10/1 hexanes/ethyl acetate to afford 4.56 g (46%) of the title compound. Rf=0.64 (4/1 hexanes/EtOAc). 1H NMR (400 MHz, CDCl3).

Workup

  1. temperatureThe mixture is cooled to −78° C.
  2. temperatureThe reaction is warmed to rt
  3. stirringstirred for 1 hour
  4. extractionextracted with Et2O
  5. dry with materialThe organic layer is dried (Na2SO4)
  6. customthe solvent is removed in vacuo
  7. customto afford crude product that
  8. customis absorbed on silica gel
  9. custompurified by flash chromatography

Sources & evidence

ORD record
ord-67b0a52f5413402b928d475bcc0c1480
Source dataset
uspto-grants-2009_10
Patent number
US07608639B2

Reaction notes

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