Lithium diisopropylamide → HCID 54098154, compound

Temperature

-78 °C

A solution of freshly prepared lithium diisopropylamide (23.0 mL of a 0.31M stock solution, 7.13 mmol) cooled to −78° C. was treated with (3,4-difluoro-phenyl)-acetic acid methyl ester (1.20 g, 6.48 mmol) in tetrahydrofuran/hexamethylphosphoramide (16.1 mL, 3:1). The resulting solution was stirred at −78° C. for 45 min. At this time, the reaction was treated with a solution of iodomethylcyclopentane (1.50 g, 7.13 mmol) in hexamethylphosphoramide (1 mL). The reaction 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 (20 mL). This mixture was poured into water (100 mL) and extracted with ethyl acetate (3×50 mL). The organics were dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 75/25 hexanes/ethyl acetate) afforded 3-cyclopentyl-2-(3,4-difluoro-phenyl)-propionic acid methyl ester (1.79 g, quant.) as a clear oil: EI-HRMS m/e calcd for C15H18F2O2 (M+) 268.1275, found 268.1278.

1. stirringThe reaction 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 (20 mL)
5. additionThis mixture was poured into water (100 mL)
6. extractionextracted with ethyl acetate (3×50 mL)
7. dry with materialThe organics were dried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated in vacuo

ORD record

ord-3ac89ac8d6da40ccb87e23ced86ce9a8

Source dataset

uspto-grants-2003_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06528543B1