Syntheses in the cyclohexanone series. II. The syntheses of 4-Ethylcyclohex-2- enone, 4-Ethylcyclohex-3-enone, and 4-Ethylidenecyclohexanone

Abstract

An attempt to synthesize 4-ethylcyclohex-2-enone by a Robinson-type ring closure gave a mixture of conjugated and non-conjugated ketones from which the conjugated isomer was isolated. 4-Ethylcyclohex-3-enone on treatment with acid yielded the same mixture of ketones. Pyrolysis of 4-carboxy-4-vinylheptanedioic acid with barium carbonate formed 4-ethylidenecyclohexanone.