2-Bromo-cyclopent-2-enol → 2-Isobutyl-cyclopent-2-enol

HRID 560128Notes

Reaction equation

HRID 560128 reaction equation
Br[C:2]1[CH:3]([OH:7])[CH2:4][CH2:5][CH:6]=1.[CH2:8]([Mg]Br)[CH:9]([CH3:11])[CH3:10]>C1COCC1.[Ni](Cl)Cl.C1(P(C2C=CC=CC=2)CCCP(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>[CH2:8]([C:2]1[CH:3]([OH:7])[CH2:4][CH2:5][CH:6]=1)[CH:9]([CH3:11])[CH3:10]

Participants

5

Reactant 2

HCID 111374622-Bromo-cyclopent-2-enol2×HCID 178418816HCID 178418816, compound

Product 1

HCID 219862102-Isobutyl-cyclopent-2-enol

Reagents, catalysts & solvents 2

HCID 2724937Dichloro(1,1'-(1,3-propanediyl)bis(1,1-diphenylphosphine-kappaP))nickelCatalystHCID 8028TetrahydrofuranSolvent

Procedure

The alcohol (Intermediate D3, 16 mmol) in THF (30 mL) at 0 EC was treated with isobutyl magnesium bromide (40 mmol). The catalyst, 1,3-bis(diphenylphosphino)propane nickel (II) chloride (0.75 mmol) (NiCl2dppp) was added in one portion and the mixture was heated to reflux for 3 h. (see: Organ et al. J. Org. Chem. 1997, 62, 1523, incorporated herein by reference). The reaction mixture was cooled to rt and quenched with sat. NH4Cl solution. The mixture was filtered and partitioned between brine and diethyl ether. The organic layer was removed and dried over Na2SO4, filtered and concentrated under vacuum. The oil was purified by chromatography on SiO2 with 20% EtOAc:Hx to yield 2-isobutyl-cyclopent-2-enol (Intermediate D4). Use of 2-isobutyl-cyclopent-2-enol (Intermediate D4) in Method A produced 4-(2-isobutyl-cyclopent-2-enylmethyl)-1,3-dihydro-imidazole-2-thione (Compound 20).

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux for 3 h. (
  3. customquenched with sat. NH4Cl solution
  4. filtrationThe mixture was filtered
  5. custompartitioned between brine and diethyl ether
  6. customThe organic layer was removed
  7. dry with materialdried over Na2SO4
  8. filtrationfiltered
  9. concentrationconcentrated under vacuum
  10. customThe oil was purified by chromatography on SiO2 with 20% EtOAc

Sources & evidence

ORD record
ord-3d3b600fb25f4a6d999db890f9c3252b
Source dataset
uspto-grants-2011_11
Patent number
US08063086B2

Reaction notes

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