Reaktion #9354

Reaktionsgleichung

alcohol

2-bromo-cyclopent-2-enol

Intermediate D3

2-bromo-cyclopent-2-enol

isobutyl magnesium bromide

→

Intermediate D4

2-isobutyl-cyclopent-2-enol

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture was heated
2. 2
   Temperaturto reflux for 3 h. (
3. 3
   Sonstigequenched with sat. NH4Cl solution
4. 4
   FiltrationThe mixture was filtered
5. 5
   Sonstigepartitioned between brine and diethyl ether
6. 6
   SonstigeThe organic layer was removed
7. 7
   Trocknendried over Na2SO4
8. 8
   Filtrationfiltered
9. 9
   Einengenconcentrated under vacuum
10. 10
    SonstigeThe oil was purified by chromatography on SiO2 with 20% EtOAc

Vorschrift

The alcohol (Intermediate D3, 16 mmol) in THF (30 mL) at 0° C. 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).

Quelle