Question

Draw a stepwise mechanism for the following reaction.

Short answer

Answer

The mechanism of the reaction

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Step-by-step solution

About the given reaction

The given starting material consists of a five-membered cyclic ring, double bonds, and a triple bond. It is treated with an acid that gives rise to a network of cyclic rings.

About the mechanism of the reaction

The given compound is rearranged and is treated with ${\mathrm{H}}_3{\mathrm{O}}^{+}$that will result in the formation of a species in which the oxygen atom has a positive charge. This species is rearranged, which gives rise to a resonance structure.

About the mechanism

The obtained cation is rearranged and treated with water. The process is repeated several times, resulting in the formation of the final product. The overall mechanism is shown below.

Mechanism of the reaction