Chapter 6, Problem 57IP

(a)

Interpretation Introduction

Interpretation: The compound (1) converts to compound (5) through the mechanistic sequence under basic conditions and in the presence of ${\text{MeO}}^{\text{-}}$ as a catalyst. The resonance structure of compound (2) that is the greatest contributor is to be interpreted.

  

Concept introduction: Resonance is the phenomenon of the interaction of lone pairs of electrons and pi electrons in a molecule. More resonance contributes to more stability of the molecule. The overall structure can be drawn as the sum of all resonating structures which is called a resonance hybrid.

(b)

Interpretation Introduction

Interpretation: The compound (1) converts to compound (5) through the mechanistic sequence under basic conditions and in the presence of ${\text{MeO}}^{\text{-}}$ as a catalyst. The missing lone pairs and curved arrows are to be interpreted for the given reaction mechanism.

  

Concept introduction: The chemical transformation can be shown by the arrow pushing method in which the curved arrows show the movement of electrons or protons. In a chemical reaction, the attack of reagent (electrophile or nucleophile), and loss of leaving group can easily be determined with the help of arrow pushing patterns.