Dimethyl methylphosphonate → Dimethyl 2-oxohept-6-ynylphosphonate

HRID 28778Notes

Reaction equation

HRID 28778 reaction equation
[CH3:1][P:2](=[O:7])([O:5][CH3:6])[O:3][CH3:4].[Li]CCCC.[C:13](OC)(=[O:19])[C:14]#[C:15][CH2:16][CH2:17][CH3:18]>C1COCC1>[O:19]=[C:13]([CH2:14][CH2:15][CH2:16][C:17]#[CH:18])[CH2:1][P:2](=[O:7])([O:5][CH3:6])[O:3][CH3:4]

Participants

5

Reactant 3

HCID 12958Dimethyl methylphosphonateHCID 87860Methyl 2-hexynoateHCID 178418339Butyllithium

Product 1

HCID 85899339Dimethyl 2-oxohept-6-ynylphosphonateYield 17%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of dimethyl methylphosphonate (2.16 mL, 20 mmol) in anhydrous THF (30 mL), cooled at −78° C. was added n-BuLi (1.6 M in hexane, 13.75 mL, 22 mmol). The mixture was stirred for 30 minutes at this temperature under nitrogen. Methyl hexynoate (1.26 g, 10 mmol) was added dropwise for 10 minutes. The mixture was stirred for 2 hours at −78° C., gradually was warm to room temperature. The mixture was quenched with addition of 1N HCl to pH 4-5. The organic layer was separated, washed with brine and dried over MgSO4. The residue was purified through flash chromatography on silica gel (MeOH:CH2Cl2=2:98) to give the product (370 mg) with colorless oil in 17% yield. 1HNMR (CDCl3, ppm) δ 1.80 (t, J=7.0 Hz, 2H), 1.95 (s, 1H), 2.24 (dt, J=2.9 and 7.0 Hz, 2H), 2.73 (t, J=7.0 Hz, 2H), 3.06 (d, J=22.7 Hz, 2H), 3.77 (s, 3H), 3.70 (s, 3H).

Workup

  1. stirringThe mixture was stirred for 2 hours at −78° C.
  2. customThe mixture was quenched with addition of 1N HCl to pH 4-5
  3. customThe organic layer was separated
  4. washwashed with brine
  5. dry with materialdried over MgSO4
  6. customThe residue was purified through flash chromatography on silica gel (MeOH:CH2Cl2=2:98)

Sources & evidence

ORD record
ord-bc089667dda5418a842b2830dd8538bd
Source dataset
uspto-grants-2008_09
Patent number
US07419999B2

Reaction notes

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