Ethyl 3-phenylprop-2-enoate → Ethyl 2,4-dioxo-6-phenylcyclohexane-1-carboxylate

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Reaction Steps

To a cooled solution of sodium ethoxide (from 2.3 g. sodium and absolute ethanol, 30 ml.) was added with shaking ethyl acetoacetate (13 g.). When homogeneous the mixture was treated with ethyl cinnamate (17.8 g.) and then heated under reflux for 18 hrs. After cooling the solution, the precipitated enolate salt (formula III) was collected by filtration and washed with acetone. Dissolution in cold water, followed by acidification with 2N-sulphuric acid (to convert the enolate salt to the corresponding dione II) afforded crystalline ethyl 2,4-dioxo-6-phenylcyclohexanecarboxylate.

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