Cyclopentanecarboxylic acid is an organic compound with the formula C5H9CO2H.

It is a colorless nonvolatile oil.

It can be produced by the palladium-catalyzed hydrocarboxylation of cyclopentene:[2] An alternative route involves the Favorskii rearrangement, which is a base-induced ring contraction of 2-chlorocyclohexanone to give the ester methyl cyclopentanecarboxylate, which can be hydrolyzed to the carboxylic acid.

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