Tetrahydrofuran → 5-Isopropenyl-2,4-dimethoxy-benzoic acid methyl ester

HRID 425208Notes

Reaction equation

HRID 425208 reaction equation
[CH3:1][O:2][C:3](=[O:15])[C:4]1[CH:9]=[C:8](Br)[C:7]([O:11][CH3:12])=[CH:6][C:5]=1[O:13][CH3:14].C([O-])([O-])=O.[Cs+].[Cs+].[CH2:22]1[CH2:26]OC[CH2:23]1>O.CCOC(C)=O.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[CH3:1][O:2][C:3](=[O:15])[C:4]1[CH:9]=[C:8]([C:22]([CH3:26])=[CH2:23])[C:7]([O:11][CH3:12])=[CH:6][C:5]=1[O:13][CH3:14]

Participants

7

Reactant 3

HCID 8028TetrahydrofuranHCID 10796Cesium carbonateHCID 3859236Methyl 5-bromo-2,4-dimethoxybenzoate

Product 1

HCID 592631485-Isopropenyl-2,4-dimethoxy-benzoic acid methyl ester

Reagents, catalysts & solvents 3

HCID 178418397HCID 178418397, compoundCatalystHCID 962WaterSolventHCID 8857Ethyl AcetateSolvent

Procedure

To potassium isopropylidene trifluoroborate (4.87 g, 32.7 mmol) and 5-bromo-2,4-dimethoxybenzoic acid methyl ester (7.5 g, 27.3 mmol) in THF (195 ml) was added Cs2CO3 (26.6 g, 81.8 mmol) in water (39 ml). The reaction was degassed and Pd(PPh3)4 (1.58 g, 1.36 mmol) added. The reaction was heated at reflux for three days then quenched by adding water and extracted with EtOAc (×2). The combined organic layers were washed with brine, dried (MgSO4), filtered and evaporated to leave an orange solid. The product was taken up in EtOAc again and the precipitate filtered. The filtrate was evaporated to dryness to yield 5-isopropenyl-2,4-dimethoxy-benzoic acid methyl ester (6.2 g). 1H NMR (Me-d3-OD) 7.68 (1H, s), 6.66 (1H, s), 5.10-5.08 (1H, m), 5.02-5.00 (1H, m), 3.93 (3H, s), 3.92 (3H, s), 3.84 (3H, s), 2.08-2.06 (3H, m). MS: [M+H]+ 237.

Workup

  1. customThe reaction was degassed
  2. temperatureThe reaction was heated
  3. temperatureat reflux for three days
  4. customthen quenched
  5. additionby adding water
  6. extractionextracted with EtOAc (×2)
  7. washThe combined organic layers were washed with brine
  8. dry with materialdried (MgSO4)
  9. filtrationfiltered
  10. customevaporated
  11. customto leave an orange solid
  12. filtrationthe precipitate filtered
  13. customThe filtrate was evaporated to dryness

Sources & evidence

ORD record
ord-4a02844dbd9345b18342311ccba8b787
Source dataset
uspto-grants-2012_01
Patent number
US08106057B2

Reaction notes

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