Iodine → α-3-Buten-1-yl-2,4-difluorobenzenemethanol

HRID 2248354Notes

Reaction equation

HRID 2248354 reaction equation
[Mg].II.Br[CH2:5][CH2:6][CH:7]=[CH2:8].[F:9][C:10]1[CH:17]=[C:16]([F:18])[CH:15]=[CH:14][C:11]=1[CH:12]=[O:13]>C(OCC)C>[OH:13][CH:12]([C:11]1[CH:14]=[CH:15][C:16]([F:18])=[CH:17][C:10]=1[F:9])[CH2:8][CH2:7][CH:6]=[CH2:5]

Participants

6

Reactant 4

HCID 807IodineHCID 21241Homoallyl bromide2×HCID 737702,4-DifluorobenzaldehydeHCID 5462224Magnesium

Product 1

HCID 14994860α-3-Buten-1-yl-2,4-difluorobenzenemethanol

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent3×

Procedure

To a stirred suspension of magnesium turnings (16.9 gm) in dry diethyl ether (1.5L) was added (argon atmosphere) a crystal of iodine and 4-bromobutene (2 ml). Soon after the reaction was initiated the remaining 4-bromobutene (101 gm) in dry diethyl ether (500 mL) was added at such a rate to maintain gentle reflux. After complete addition, the mixture was heated to reflux for 1 hour. 2,4-Difluorobenzaldehyde (100 gm) in dry diethyl ether (400 mL) was then added dropwise with a gentle reflux. The mixture was now heated for 2 hours and allowed to cool to room temperature. The entire contents of the flask were poured on 6L ice-water containing 200 ml concentrated HCl. The organic phase was separated, washed with water, saturated NaHCO3, water and dried (Na2SO4). Removal of ether in vacuo provided crude 5-hydroxy-5-(2,4-difluorophenyl)pentene as an oil (136.5 gm) which was used in the next step.

Workup

  1. additionwas added at such a rate
  2. temperatureto maintain gentle reflux
  3. additionAfter complete addition
  4. temperaturethe mixture was heated
  5. temperatureto reflux for 1 hour
  6. temperatureThe mixture was now heated for 2 hours
  7. customThe organic phase was separated
  8. washwashed with water, saturated NaHCO3, water
  9. dry with materialdried (Na2SO4)
  10. customRemoval of ether in vacuo

Sources & evidence

ORD record
ord-d8008988cc3c4c2c959e4e070e990700
Source dataset
uspto-grants-1991_08
Patent number
US05039676

Reaction notes

Loading…