Chapter 22, Problem 53P

Interpretation Introduction

Interpretation: The stepwise mechanism for the given Robinson annulation is to be drawn.

Concept introduction: Robinson annulation is a combination of Michael addition and intramolecular aldol condensation reactions. It takes place between an $\text{α,β}$-unsaturated carbonyl compound and a carbonyl compound. The enolate formation takes place from carbonyl compound which attacks the $\text{α,β}$-unsaturated carbonyl compound to form $1,5$-dicarbonyl compound. This compound undergoes intramolecular aldol condensation which leads to the formation of a ring.