Chapter 17, Problem 64P

(a)

Interpretation Introduction

Interpretation: An acid-catalyzed and a base-catalyzed rearrangement of a $\beta ,\gamma \text{-unsaturated carbonyl}$ compound to a more stable $\alpha ,\beta \text{-unsaturated carbonyl}$ compound has to be proposed.

Concept introduction: The carbon which is adjacent to the carbonyl group is known as $\alpha \text{-carbon}$, followed next by $\beta \text{-carbon}$ and $\gamma \text{-carbon}$.  The $\alpha ,\beta \text{-unsaturated carbonyl}$ compounds are a type of carbonyl compounds where there is a double bond between the $\alpha$ and $\beta \text{-carbon}$.  The $\beta ,\gamma \text{-unsaturated carbonyl}$ compounds are those where there is a double bond between the $\beta$ and $\gamma$ carbon.  The $\alpha ,\beta \text{-unsaturated carbonyl}$ compounds are most stable than the $\beta ,\gamma \text{-unsaturated carbonyl}$ compounds and hence rearrangement takes place in presence of either an acid or a base.

(b)

Interpretation Introduction

Interpretation: An acid-catalyzed and a base-catalyzed rearrangement of a $\beta ,\gamma \text{-unsaturated carbonyl}$ compound to a more stable $\alpha ,\beta \text{-unsaturated carbonyl}$ compound has to be proposed.

Concept introduction: The carbon which is adjacent to the carbonyl group is known as $\alpha \text{-carbon}$, followed next by $\beta \text{-carbon}$ and $\gamma \text{-carbon}$.  The $\alpha ,\beta \text{-unsaturated carbonyl}$ compounds are a type of carbonyl compounds where there is a double bond between the $\alpha$ and $\beta \text{-carbon}$.  The $\beta ,\gamma \text{-unsaturated carbonyl}$ compounds are those where there is a double bond between the $\beta$ and $\gamma$ carbon.  The $\alpha ,\beta \text{-unsaturated carbonyl}$ compounds are most stable than the $\beta ,\gamma \text{-unsaturated carbonyl}$ compounds and hence rearrangement takes place in presence of either an acid or a base.