Cesium carbonate → 4-Isopropenyl-2-methyl-benzoic acid methyl ester

HRID 41909

Reaction equation

HRID 41909 reaction equation
[CH3:1][O:2][C:3](=[O:12])[C:4]1[CH:9]=[CH:8][C:7](Br)=[CH:6][C:5]=1[CH3:11].[C:13](B1OC(C)(C)C(C)(C)O1)([CH3:15])=[CH2:14].C(=O)([O-])[O-].[Cs+].[Cs+]>O1CCOCC1>[CH3:1][O:2][C:3](=[O:12])[C:4]1[CH:9]=[CH:8][C:7]([C:13]([CH3:15])=[CH2:14])=[CH:6][C:5]=1[CH3:11]

Participants

5

Reactant 3

HCID 10796Cesium carbonateHCID 109974264,4,5,5-Tetramethyl-2-(prop-1-en-2-yl)-1,3,2-dioxaborolaneHCID 22031226Methyl 4-bromo-2-methylbenzoate

Product 1

HCID 592165214-Isopropenyl-2-methyl-benzoic acid methyl esterYield 88.5%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Conditions

Temperature
120 °C

Procedure

4-Bromo-2-methyl-benzoic acid methyl ester (4 g, 17.46 mmol), isopropenylboronic acid pinacol ester (3.228 g, 19.21 mmol) and cesium carbonate (19.913 g, 61.11 mmol) were treated with a degassed solution of 15 ml dioxane/5 ml water. After 5 min stirring [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex (0.718 g, 0.873 mmol) was added and heated to 120° C. for 40 min in the microwave. The reaction mixture was filtered over cellulose; washed with 20 ml dioxane and concentrated in vacuo. The residue was purified by 120 g silica gel chromatography (gradient elution 0-50% ethyl acetate in hexane during 50 min) to yield 4-Isopropenyl-2-methyl-benzoic acid methyl ester (2.94 g, 15.45 mmol). MS (ESI) 191.3 (M+H)+

Workup

  1. additionwas added
  2. filtrationThe reaction mixture was filtered over cellulose
  3. washwashed with 20 ml dioxane
  4. concentrationconcentrated in vacuo
  5. customThe residue was purified by 120 g silica gel chromatography (gradient elution 0-50% ethyl acetate in hexane during 50 min)

Sources & evidence

ORD record
ord-023600dfa07a48a7b0cac71e0606de8b
Source dataset
uspto-grants-2013_09
Patent number
US08536166B2

Linked notes

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