Ethyl 2-ethyl-4-oxocyclopent-2-enecarboxylate → Cyclopentanecarboxylic acid, 2-ethyl-4-oxo-, ethyl ester

HRID 2204513Notes

Reaction equation

[CH2:1]([C:3]1[CH:4]([C:9]([O:11][CH2:12][CH3:13])=[O:10])[CH2:5][C:6](=[O:8])[CH:7]=1)[CH3:2]>[Pd].CCOC(C)=O>[CH2:1]([CH:3]1[CH2:7][C:6](=[O:8])[CH2:5][CH:4]1[C:9]([O:11][CH2:12][CH3:13])=[O:10])[CH3:2]

Participants

Conditions

Temperature: 0 °C

Procedure

A round-bottom flask was charged with 10% palladium on carbon (10 g, 9.4 mmol). The flask was cooled to about 0° C. and EtOAc (400 mL) was added under a nitrogen atmosphere. The cooling bath was removed and ethyl 2-ethyl-4-oxocyclopent-2-enecarboxylate (47.8 g, 263 mmol, Preparation #CC.1) was added. Hydrogen gas was bubbled through the mixture for about 5 min and the mixture was then stirred under a hydrogen atmosphere for about 48 h. The hydrogen source was removed and the mixture was bubbled with nitrogen for about 5 min and was filtered through a pad of Celite®. The filter cake was rinsed with EtOAc (400 mL). The filtrate was concentrated under reduced pressure to give ethyl 2-ethyl-4-oxocyclopentanecarboxylate (about 9:1 mixture cis: trans) (48.0 g, 99%) as a yellow liquid: 1H NMR (CDCl3) δ 4.23-4.10 (m, 2H), 3.22 (m, 1H), 2.59-2.50 (m, 1H), 2.44-2.28 (m, 3H), 2.26-2.16 (m, 1H), 1.58-1.46 (m, 1H), 1.41-1.30 (m, 1H), 1.30-1.23 (m, 3H), 1.02-0.91 (m, 3H).

Workup

customThe cooling bath was removed
customHydrogen gas was bubbled through the mixture for about 5 min
customThe hydrogen source was removed
customthe mixture was bubbled with nitrogen for about 5 min
filtrationwas filtered through a pad of Celite®
washThe filter cake was rinsed with EtOAc (400 mL)
concentrationThe filtrate was concentrated under reduced pressure

Sources & evidence

ORD record: ord-6ff978bd82324bdea74b6be9a9d9c96d
Source dataset: uspto-grants-2016_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09365579B2

Reaction notes

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