Bromomethylcyclopropane → 1-(3-Bromophenyl)pent-4-en-1-one

HRID 30558Notes

Reaction equation

HRID 30558 reaction equation
[Mg].Br[CH2:3][CH:4]1[CH2:6][CH2:5]1.[Br:7][C:8]1[CH:9]=[C:10]([CH:17]=[CH:18][CH:19]=1)[C:11](N(OC)C)=[O:12]>C1COCC1>[Br:7][C:8]1[CH:9]=[C:10]([C:11](=[O:12])[CH2:6][CH2:5][CH:4]=[CH2:3])[CH:17]=[CH:18][CH:19]=1

Participants

5

Reactant 3

HCID 81503BromomethylcyclopropaneHCID 5462224MagnesiumHCID 121628753-Bromo-N-methoxy-N-methylbenzamide

Product 1

HCID 146658981-(3-Bromophenyl)pent-4-en-1-oneYield 98%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent3×

Procedure

A mixture of magnesium (0.48 g, 20.29 mmol) in THF was treated dropwise with (bromomethyl)cyclopropane (2.49 g, 18.45 mmol) in THF, heated at reflux temperature for 1 hour, poured into a cold (0° C.) mixture of 3-bromo-N-methoxy-N-methylbenzamide (2.5 g, 10.24 mmol) and THF, allowed to come to room temperature, stirred for 10 min, quenched with aqueous NH4Cl and extracted with ethyl ether. The organic extracts were combined, dried over MgSO4 and concentrated in vacuo. Purification of the resultant residue on silica gel (ISCO) using hexanes/EtOAc 10/1 as the eluting solvents gave a clear oil (2.4 g, 54% yield), MS m/e (M−H)+ 239; 1H NMR (400 MHz, DMSO-d6) 2.3 (m, 2H), 3.1 (t, J=7.19 Hz, 2H), 5.02 (m, 2H), 5.8 (m, 1H), 7.47 (t, J=7.93 Hz, 2H), 7.77 (dd, J=7.08, 2.2 Hz), 7.94 (dd, J=7.81, 1.58 Hz), 8.04 (t, J=1.83 Hz, 1H).

Workup

  1. temperatureheated
  2. temperatureat reflux temperature for 1 hour
  3. customto come to room temperature
  4. customquenched with aqueous NH4Cl
  5. extractionextracted with ethyl ether
  6. dry with materialdried over MgSO4
  7. concentrationconcentrated in vacuo
  8. customPurification of the resultant residue on silica gel (ISCO)

Sources & evidence

ORD record
ord-c43cd08b2a054b33830303d1f093bab4
Source dataset
uspto-grants-2008_09
Patent number
US07423158B2

Reaction notes

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