反応 #57037

反応方程式

alcohol

2-bromo-3-methyl-cyclopent-2-enol

ethyl magnesium bromide

→

2-ethyl-3-methyl-cyclopent-2-enol

溶媒

THF

反応条件

後処理

1. 1
   温度the mixture was heated
2. 2
   温度to reflux for 3 hours
3. 3
   その他quenched with sat. NH4Cl solution
4. 4
   ろ過The mixture was filtered
5. 5
   その他partitioned between brine and diethyl ether
6. 6
   その他The organic layer was removed
7. 7
   乾燥dried over Na2SO4
8. 8
   ろ過filtered
9. 9
   濃縮concentrated under vacuum
10. 10
    その他The oil was purified by chromatography on SiO, with 20% EtOAc

実験手順

The alcohol (Intermediate V2, 16 mmol) in THF (30 mL) at 0° C. was treated with ethyl 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 hours following the procedure of 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 SiO, with 20% EtOAc:Hx to yield 2-ethyl-3-methyl-cyclopent-2-enol (Intermediate V3). Use of the alcohol (Intermediate V3) in the applicable steps of Method A and Method P produced 4-(2-ethyl-3-methyl-cyclopent-2-enylmethyl)-1,3-dihydro-imidazol-2-one (Compound 64). 1NMR (300 MHz, CD3OD-d4): δ 6.03 (s, 1H), 2.88 (brs, 1H), 2.65-2.59 (m, 1H), 2.27-1.83 (series of m, 6H), 1.62 (s, 3H), 1.54-1.45 (m, 1H), 0.97 (t, J=6 Hz, 3H).

出典