Carbon tetrabromide → 3,5-Bis(4-vinylbenzyloxy)benzyl bromide

HRID 322605Notes

Reaction equation

HRID 322605 reaction equation
[H-].[H-].[H-].[H-].[Li+].[Al+3].[CH:7]([C:9]1[CH:35]=[CH:34][C:12]([CH2:13][O:14][C:15]2[CH:16]=[C:17]([CH:21]=[C:22]([O:24][CH2:25][C:26]3[CH:31]=[CH:30][C:29]([CH:32]=[CH2:33])=[CH:28][CH:27]=3)[CH:23]=2)[C:18]([O-])=O)=[CH:11][CH:10]=1)=[CH2:8].[OH-].[Na+].C(C1C=CC(COC2C=C(C=C(OCC3C=CC(C=C)=CC=3)C=2)CO)=CC=1)=C.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C(Br)(Br)(Br)[Br:86]>C1COCC1.CCCCCC.CC(C)=O.C(OCC)C.O.CCCCCC>[CH:7]([C:9]1[CH:35]=[CH:34][C:12]([CH2:13][O:14][C:15]2[CH:16]=[C:17]([CH:21]=[C:22]([O:24][CH2:25][C:26]3[CH:31]=[CH:30][C:29]([CH:32]=[CH2:33])=[CH:28][CH:27]=3)[CH:23]=2)[CH2:18][Br:86])=[CH:11][CH:10]=1)=[CH2:8]

Participants

12

Reactant 6

HCID 11205Carbon tetrabromideHCID 11776TriphenylphosphineHCID 14798Sodium HydroxideHCID 21226445Aluminium lithium hydrideHCID 220111503,5-Di(4-vinylbenzyloxy)benzoateHCID 232481633,5-Di(4-vinylbenzyloxy)benzylalcohol2×

Product 1

HCID 184339453,5-Bis(4-vinylbenzyloxy)benzyl bromide

Reagents, catalysts & solvents 5

HCID 962WaterSolvent3×HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent3×HCID 8058HexaneSolventHCID 21880519Acetone hexaneSolvent

Procedure

A 1 L flask is charged with 10.0 g (268.6 mmol, 2.3 eq) of LiAlH4 in THF (250 ml) under an argon atmosphere. The resultant solution is cooled with an ice bath and 46.9 g (116.9 mmol) of ester (2A) in THF (250 ml) is added dropwise with stirring and the mixture, stirred over a 2 hour period. Thereafter water (10 ml) and 15% NaOH (10 ml) and finally water (24 ml) is added to the mixture. The grey precipitate is filtered and the filtrate is washed with diethylether. Thereafter water (500 ml) is added and the organic phase is collected. The remaining aqueous phase is further extracted with diethylether (3×500 ml) and the organic phases are collected and combined, dried over MgSO4 and evaporated to dryness. A colourless oil is obtained (38.7 g, 88.5%). Addition of a little hexane effects precipitation of white crystals of 3,5-di(4-vinylbenzyloxy)benzylalcohol (2B). A 1 L flask is charged with 64.5 g (173 mmol) of (2B) in THF (250 ml) under an argon atmosphere. Thereafter, 68.1 g (260 mmol, 1.5 eq) of PPh3 and then 86.2 g (260 mmol, 1.5 eq) of CBr4 are added and the resultant mixture stirred gently for 1 hour in an ice bath whereupon a milky suspension is obtained. To this suspension is added water (600 ml) and diethylether (400 ml). The organic phase is collected and the aqueous phase is further extracted with diethylether (2×500 ml). The organic phases are collected and combined, dried over MgS04 and evaporated to dryness. A yellow oil is obtained which is dissolved in hexane/acetone 9:1 and filtered over Kieselgel. The resultant solution is left to recrystallise to yield fine white crystals of 3,5-di(4-vinylbenzyloxy)benzylbromide (2).

Workup

  1. stirringthe mixture, stirred over a 2 hour period
  2. filtrationThe grey precipitate is filtered
  3. washthe filtrate is washed with diethylether
  4. additionThereafter water (500 ml) is added
  5. customthe organic phase is collected
  6. extractionThe remaining aqueous phase is further extracted with diethylether (3×500 ml)
  7. customthe organic phases are collected
  8. dry with materialdried over MgSO4
  9. customevaporated to dryness
  10. customA colourless oil is obtained (38.7 g, 88.5%)
  11. customis obtained
  12. customThe organic phase is collected
  13. extractionthe aqueous phase is further extracted with diethylether (2×500 ml)
  14. customThe organic phases are collected
  15. customdried over MgS04
  16. customevaporated to dryness
  17. customA yellow oil is obtained which
  18. filtrationfiltered over Kieselgel
  19. waitThe resultant solution is left
  20. customto recrystallise

Sources & evidence

ORD record
ord-4e079c6069604f52ac863a4abfcda7f3
Source dataset
uspto-grants-2001_04
Patent number
US06211316B1

Reaction notes

Loading…