Diisopropylamine → Ethyl 2-oxo-3-phenylcyclopentanecarboxylate

Temperature

-78 °C

To a solution of diisopropylamine (6.62 mL, 46.8 mmol) in THF (200 mL) at −78° C. was added a 1.6 M solution of n-butyllithium in hexanes (29.3 mL, 46.8 mmol). The solution was stirred for 30 min at −78° C. and treated with a solution of 2-phenylcyclopentanone (5 g, 31.2 mmol) in 50 mL of dry THF. After stirring for 30 min at −78° C., ethyl carbonocyanidate (3.36 mL, 34.3 mmol) was added to the reaction mixture. The resulting solution was warmed to 25° C. with stirring over 3 h. The reaction mixture was quenched with 10 mL of water, washed with brine, dried over anhydrous sodium sulfate, concentrated in vacuo. The residue was purified by column chromatography on silica gel to afford ethyl 2-oxo-3-phenylcyclopentanecarboxylate (5.3 g, 22.82 mmol, 73% yield) as a colorless oil. LC-MS (M+K)+=273.2. 1H NMR (500 MHz, chloroform-d) δ ppm 7.32-7.39 (2H, m), 7.25-7.31 (1H, m), 7.19-7.25 (2H, m), 4.18-4.32 (2H, m), 3.29-3.55 (2H, m), 1.87-2.62 (4H, m), 1.28-1.39 (3H, m).

1. stirringAfter stirring for 30 min at −78° C.
2. temperatureThe resulting solution was warmed to 25° C.
3. stirringwith stirring over 3 h
4. customThe reaction mixture was quenched with 10 mL of water
5. washwashed with brine
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated in vacuo
8. customThe residue was purified by column chromatography on silica gel

ORD record

ord-4f000be7d37647eca34c03452e59c6db

Source dataset

uspto-grants-2014_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08637523B2