[(4-Bromophenyl)methyl]triphenylphosphanium bromide → Methyl 4-(1-(4-bromophenyl)-4-methylpent-1-en-2-yl)benzoate

HRID 537508Notes

Reaction equation

HRID 537508 reaction equation
[Br-].[Br:2][C:3]1[CH:28]=[CH:27][C:6]([CH2:7][P+](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=[CH:5][CH:4]=1.C[Si]([N-][Si](C)(C)C)(C)C.[Li+].[CH3:39][CH:40]([CH3:54])[CH2:41][C:42]([C:44]1[CH:53]=[CH:52][C:47]([C:48]([O:50][CH3:51])=[O:49])=[CH:46][CH:45]=1)=O>C1(C)C=CC=CC=1.O.C(OCC)(=O)C>[Br:2][C:3]1[CH:4]=[CH:5][C:6]([CH:7]=[C:42]([C:44]2[CH:45]=[CH:46][C:47]([C:48]([O:50][CH3:51])=[O:49])=[CH:52][CH:53]=2)[CH2:41][CH:40]([CH3:54])[CH3:39])=[CH:27][CH:28]=1

Participants

7

Reactant 3

HCID 2724858[(4-Bromophenyl)methyl]triphenylphosphanium bromideHCID 2733832Lithium HexamethyldisilazideHCID 56593012Methyl 4-(3-methylbutanoyl)benzoate

Product 1

HCID 68157244Methyl 4-(1-(4-bromophenyl)-4-methylpent-1-en-2-yl)benzoateYield 61%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 1140TolueneSolvent2×HCID 8857Ethyl AcetateSolvent

Conditions

Temperature
0 °C

Procedure

4-Bromobenzyltriphenylphosphonium bromide (2.07 g, 4.40 mmol) was suspended in toluene (4.0 mL) and cooled to 0° C. Lithium bis(trimethylsilyl)amide (4.04 mL, 1.0 M in toluene) was added. The ice bath was removed and the reaction was allowed to warm to room temperature and stir for 1 hour. A solution of Intermediate (10) (180 mg, 0.817 mmol) in toluene (0.8 mL) was then added drop-wise, and the reaction was allowed to stir for 18 hours. The reaction was diluted with water and ethyl acetate. The layers were separated and the aqueous was extracted three times with ethyl acetate. The combined organics were washed twice with 1N HCl and once with brine, then dried over magnesium sulfate, filtered, and concentrated. The crude solid was taken up in heptane and the remaining solids (triphenylphospine oxide) were filtered off. The filtrate was concentrated and purified by column chromatography (0-10% ethyl acetate in heptane) to give methyl 4-(1-(4-bromophenyl)-4-methylpent-1-en-2-yl)benzoate (184.7 mg, 61%) as an approximate 1:1 mixture of E/Z isomers. 1H NMR (400 MHz, CDCl3, δ): 8.04-8.00 (m, 2H), 7.97-7.92 (m, 2H), 7.50-7.46 (m, 4H), 7.22-7.16 (m, 6H), 6.77-6.72 (m, 2H), 6.69 (s, 1H), 6.39 (s, 1H), 3.92 (s, 3H), 3.90 (s, 3H), 2.58 (d, J=7.4 Hz, 2H), 2.37 (dd, J=7.2, 1.2 Hz, 2H), 1.68-1.57 (m, 1H), 1.51 (dt, J=13.5, 6.8 Hz, 1H), 0.88 (d, J=6.6 Hz, 6H), 0.78 (d, J=6.6 Hz, 6H).

Workup

  1. customThe ice bath was removed
  2. temperatureto warm to room temperature
  3. stirringto stir for 18 hours
  4. customThe layers were separated
  5. extractionthe aqueous was extracted three times with ethyl acetate
  6. washThe combined organics were washed twice with 1N HCl and once with brine
  7. dry with materialdried over magnesium sulfate
  8. filtrationfiltered
  9. concentrationconcentrated
  10. filtrationthe remaining solids (triphenylphospine oxide) were filtered off
  11. concentrationThe filtrate was concentrated
  12. custompurified by column chromatography (0-10% ethyl acetate in heptane)

Sources & evidence

ORD record
ord-13e88f748617403d830af9a1bf43615e
Source dataset
uspto-grants-2014_10
Patent number
US08859591B2

Reaction notes

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