CID 406 → Dimethyl 2-oxo-2-phenylethylphosphonate

HRID 1283223Notes

Reaction equation

HRID 1283223 reaction equation
[CH3:1][P:2](=[O:7])([O:5][CH3:6])[O:3][CH3:4].P(=O)([O-])[O-].C([Li])CCC.[C:17](OC)(=[O:24])[C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1>O1CCCC1.CCCCCC.C(O)(=O)C>[O:24]=[C:17]([C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)[CH2:1][P:2](=[O:7])([O:5][CH3:6])[O:3][CH3:4]

Participants

8

Reactant 4

HCID 406CID 406HCID 7150Methyl BenzoateHCID 12958Dimethyl methylphosphonateHCID 178418339Butyllithium

Product 1

HCID 569473Dimethyl 2-oxo-2-phenylethylphosphonateYield 51.1%

Reagents, catalysts & solvents 3

HCID 176Acetic AcidSolventHCID 8028TetrahydrofuranSolventHCID 8058HexaneSolvent

Procedure

A solution of 74.5 g (600 mmoles) dimethyl methylphosphonate (Aldrich) in 750 ml dry tetrahydrofuran was cooled to -78° in a dry nitrogen atmosphere. To the stirred phosphonate solution was added 265 ml of 2.34 M n-butyllithium in hexane solution (Alfa Inorganics, Inc.) dropwise over a period of 30 minutes at such a rate that the reaction temperature never rose above -65°. After an additional 5 minutes stirring at -78°, 41 g (300 mmole) of methyl benzoate was added dropwise at a rate that kept the reaction temperature less than -70° (10 minutes). After 1 hour at -78° the reaction mixture was allowed to warm to ambient temperature, neutralized with 35 ml acetic acid and rotary evaporated to a white gel. The gelatinous material was taken up in 75 ml water, the aqueous phase extracted with 300 ml portions of ether (3x), the combined organic extracts were backwashed (50 cc H2O), dried (MgSO4), and concentrated (water aspirator) to a crude residue and distilled, b.p. 130°-5° (0.4 mm) to give 35 g (29%) dimethyl 2-oxo-2-phenylethylphosphonate (2a).

Workup

  1. customthe reaction temperature less than -70° (10 minutes)
  2. waitAfter 1 hour at -78° the reaction mixture was allowed
  3. customrotary evaporated to a white gel
  4. extractionthe aqueous phase extracted with 300 ml portions of ether (3x)
  5. dry with materialdried (MgSO4)
  6. concentrationconcentrated (water aspirator) to a crude residue
  7. distillationdistilled

Sources & evidence

ORD record
ord-f92e93a049bc402da3cdfc8910a6176b
Source dataset
uspto-grants-1976_08
Patent number
US03974213

Reaction notes

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