Chapter 22, Problem 63P

Interpretation Introduction

Interpretation: The synthesis of $\text{2-methylcyclopentanone}$ from cyclohexene is to be devised.

Concept introduction: In the presence of ozone and ${\text{CH}}_{\text{3}}{\text{SCH}}_{\text{3}}$, oxidative cleavage occurs. In oxidative cleavage both the sigma and pi bond of the alkene is broken and two carbonyl compounds are formed. When ozone is added to the alkene, unstable intermediate molozonide is formed which rearranges to ozonide. This ozonide is reduced to form two carbonyl compounds in presence of ${\text{CH}}_{\text{3}}{\text{SCH}}_{\text{3}}$.

Dieckmann condensation reaction is a intramolecular condensation reaction in diester. In Dieckmann condensation reaction, the base abstracts the acidic proton from $\text{α}$ carbon atom of one ester group to form enolate. This enolate reacts with carbonyl compound of other ester that leads to the formation of $\text{β}$-ketoester.