Question

Draw the product Y of the following reaction sequence. Y was an intermediate in the remarkable synthesis of cyclooctatetraene by Wilstatter in 1911.

Short answer

Mechanism of the given reaction

Step-by-step solution

Synthesis of cyclooctatetraene

It is an unsaturated derivative of cyclooctane. It has alternating single and double bonds. The compound is not aromatic due to its non-planar structure. But the dianion of the compound is aromatic.

Cyclooctatetrene is also called [8]Annulene due to the alternating single and double bond structure.

Hoffmann elimination

In Hoffmann elimination, amines undergo polyalkylation to produce a Hoffmann elimination product.

The reagents used in the reaction are methyl iodide and silver oxide.

The reactive involves the conversion of an amine to its quarternary iodide salt by the addition of methyl iodide.

This quaternary salt is treated with silver oxide and water to form the quaternary hydroxide, which on heating removes the amine group with beta hydrogen.

Mechanism of the given reaction

The given amine undergoes two consecutive Hoffmann degradation reactions to remove the amine as trimethylamine from the compound. The product obtained is 1,3,5-cyclooctatriene.

Mechanism of the given reaction