Ethyl 2:2-dimethylcyclopentan-1-one-4-carboxylate (Bardhan, Banerji, and Bose, J., 1935, 1128) readily condenses with ethyl cyanoacetate to give ethyl 4-carbethoxy-2:2-dimethylcyclopentylidenecyanoacetate. This on catalytic hydrogenation followed by hydrolysis affords 4-carboxy-2:2-dimethylcyclopentane- 1-acetic acid. The corresponding lead salt on pyrolysis furnishes (±)-β-fenchocamphorone. This synthesis establishes the correctness of the structure of β-fenchocamphorone and consequently of β-fenchene.