Tetrahydrofuran → 3-Benzylind-2-en-1-one

HRID 1576171Notes

Reaction equation

HRID 1576171 reaction equation
[CH3:1]P(=O)(OCC)OCC.O1CCCC1.C([Li])CCC.[CH:20](=[C:27]1[C:36]2[C:31](=[CH:32][CH:33]=[CH:34][CH:35]=2)[C:29](=[O:30])O1)[C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1>CCCCCC.O>[CH2:20]([C:27]1[C:36]2[C:31](=[CH:32][CH:33]=[CH:34][CH:35]=2)[C:29](=[O:30])[CH:1]=1)[C:21]1[CH:22]=[CH:23][CH:24]=[CH:25][CH:26]=1

Participants

7

Reactant 4

HCID 8028Tetrahydrofuran2×HCID 12685Diethyl methylphosphonateHCID 68464BenzylidenephthalideHCID 178418339Butyllithium

Product 1

HCID 128193553-Benzylind-2-en-1-one

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8058HexaneSolvent

Procedure

Diethyl methylphosphonate (1.94 g.) suspended in 50 ml. of dry tetrahydrofuran is treated with 1.1 equivalents of butyl lithium in hexane under nitrogen at about -78°. After 10 minutes, one equivalent of benzalphthalide in 10 ml. of tetrahydrofuran is added while maintaining the temperature at about -78°. The reaction mixture is allowed to warm to room temperature and then left to stand at room temperature for 3 hours. The reaction mixture is diluted with water and then extracted with ether. The ether extracts are combined, washed with water, dried and the solvent removed under vacuum. The residue is chromatographed on silica eluting with methylene chloride:hexane (4:1) to afford 3-benzylind-2-en-1-one and a small amount of starting material.

Workup

  1. temperaturewhile maintaining the temperature at about -78°
  2. waitleft
  3. waitto stand at room temperature for 3 hours
  4. extractionextracted with ether
  5. washwashed with water
  6. customdried
  7. customthe solvent removed under vacuum
  8. customThe residue is chromatographed on silica eluting with methylene chloride:hexane (4:1)

Sources & evidence

ORD record
ord-7a37f4dbe8c643d38b16966ebb9a41a0
Source dataset
uspto-grants-1976_09
Patent number
US03979458

Reaction notes

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