Reaktion #624620

Reaktionsgleichung

isopropylmagnesium chloride lithium chloride

ethyl 4-iodobenzoate

cyclopentanecarbonyl chloride

→

ethyl 4-(cyclopentanecarbonyl)benzoate

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto warm to −15° C.
2. 2
   workup.STIRRINGstir for 8 minutes
3. 3
   TemperaturThe solution was cooled back to −40° C.
4. 4
   Temperaturto gradually warm to 0° C. over 3 hours
5. 5
   SonstigeThe mixture was quenched with 1 N HCl (20 mL)
6. 6
   workup.ADDITIONdiluted with ethyl acetate
7. 7
   workup.STIRRINGThe mixture was stirred at room temperature for 5 min
8. 8
   SonstigeA white precipitate formed
9. 9
   FiltrationThe mixture was filtered through celite
10. 10
    Sonstigethe filtrate transferred to a separatory funnel
11. 11
    SonstigeThe layers were separated
12. 12
    ExtraktionThe aqueous was extracted twice with ethyl acetate
13. 13
    WaschenThe combined organics were washed with brine
14. 14
    Trocknendried over sodium sulfate
15. 15
    Filtrationfiltered
16. 16
    Einengenconcentrated
17. 17
    SonstigePurification by column chromatography (0-20% ethyl acetate in heptane)

Vorschrift

At −40° C., isopropylmagnesium chloride lithium chloride (13.9 mL, 1.3 M in THF) was added dropwise to a solution of ethyl 4-iodobenzoate (4971 mg, 18.01 mmol) in tetrahydrofuran (30 mL). The solution was stirred at −40° C. for 50 minutes. Copper(I) iodide (1.03 g, 5.4 mmol) was added. The mixture was allowed to warm to −15° C. and stir for 8 minutes. The solution was cooled back to −40° C. and cyclopentanecarbonyl chloride (3580 mg, 27.0 mmol) was added dropwise. The mixture was allowed to gradually warm to 0° C. over 3 hours. The mixture was quenched with 1 N HCl (20 mL) and diluted with ethyl acetate. The mixture was stirred at room temperature for 5 min. A white precipitate formed. The mixture was filtered through celite and the filtrate transferred to a separatory funnel. The layers were separated. The aqueous was extracted twice with ethyl acetate. The combined organics were washed with brine, dried over sodium sulfate, filtered and concentrated. Purification by column chromatography (0-20% ethyl acetate in heptane) gave ethyl 4-(cyclopentanecarbonyl)benzoate as an oil. 1H NMR (400 MHz, CDCl3, δ): 8.13-8.08 (m, 2H), 8.02-7.97 (m, 2H), 4.39 (q, J=7.22 Hz, 2H), 3.77-3.65 (m, 1H), 1.99-1.79 (m, 4H), 1.77-1.60 (m, 4H), 1.40 (t, J=7.22 Hz, 3H).

Quelle