反应详情

温度

-78 °C

A solution of freshly prepared lithium diisopropylamide (430.55 mL of a 0.3M stock solution, 129.16 mmol) cooled to −78° C. was treated with (4-nitro-phenyl)-acetic acid ethyl ester (prepared as in Example 22A, 26.32 g, 125.83 mmol) in tetrahydrofuran/hexamethylphosphoramide (312.5 mL, 3:1). The resulting solution was stirred at −78° C. for 45 min. Iodomethylcyclopentane (27.75 g, 132.1 mmol) was then added in hexamethylphosphoramide (27.75 mL). The mixture was stirred at −78° C. for 4 h. The reaction was then warmed to 25° C. and was stirred at 25° C. for 16 h. The reaction mixture was then quenched by the dropwise addition of a saturated aqueous ammonium chloride solution (250 mL). This mixture was concentrated in vacuo. The residue was diluted with water (250 mL) and extracted with ethyl acetate (3×300 mL). The combined organic layers were washed with a saturated aqueous lithium chloride solution (2×250 mL), dried over magnesium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 98/2 hexanes/ethyl acetate) afforded 3-cyclopentyl-2-(4-nitro-phenyl)-propionic acid ethyl ester (28.30 g, 77.2%) as a yellow oil: EI-HRMS m/e calcd for C16H21NO4 (M+) 291.1470, found 291.1470.

1. stirringThe mixture was stirred at −78° C. for 4 h
2. temperatureThe reaction was then warmed to 25° C.
3. stirringwas stirred at 25° C. for 16 h
4. customThe reaction mixture was then quenched by the dropwise addition of a saturated aqueous ammonium chloride solution (250 mL)
5. concentrationThis mixture was concentrated in vacuo
6. additionThe residue was diluted with water (250 mL)
7. extractionextracted with ethyl acetate (3×300 mL)
8. washThe combined organic layers were washed with a saturated aqueous lithium chloride solution (2×250 mL)
9. dry with materialdried over magnesium sulfate
10. filtrationfiltered
11. concentrationconcentrated in vacuo