Chapter 25.1, Problem 1P

Interpretation Introduction

(a)

Interpretation: The given reaction is to be classified as an electrocyclic reaction, cycloaddition, or a sigmatropic rearrangement. The sigma bonds that are broken or formed in the given reaction are to be labeled.

Concept introduction: A chemical reaction that involves $\left[4+2\right]$ cycloaddition is called Diels-Alder reaction. The reactant molecules that give rise to the product are diene and dienophile. The rate of reaction is fast when the electronegative group is attached to dienophile. In the sigmatropic rearrangement, the migration of the sigma bond takes place. Electrocyclic reactions involve the conversion of $\text{σ}$ bonds into $\text{π}$ bonds or $\text{π}$ bonds into $\text{σ}$ bonds.

Interpretation Introduction

(b)

Interpretation: The given reaction is to be classified as an electrocyclic reaction, cycloaddition, or a sigmatropic rearrangement. The sigma bonds that are broken or formed in the given reaction are to be labeled.

Concept introduction: A chemical reaction that involves $\left[4+2\right]$ cycloaddition is called Diels-Alder reaction. The reactant molecules that give rise to the product are diene and dienophile. The rate of reaction is fast when the electronegative group is attached to dienophile. In the sigmatropic rearrangement, the migration of the sigma bond takes place. Electrocyclic reactions involve the conversion of $\text{σ}$ bonds into $\text{π}$ bonds or $\text{π}$ bonds into $\text{σ}$ bonds.

Interpretation Introduction

(c)

Interpretation: The given reaction is to be classified as an electrocyclic reaction, cycloaddition, or a sigmatropic rearrangement. The sigma bonds that are broken or formed in the given reaction are to be labeled.

Concept introduction: A chemical reaction that involves $\left[4+2\right]$ cycloaddition is called Diels-Alder reaction. The reactant molecules that give rise to product are diene and dienophile. The rate of reaction is fast when the electronegative group is attached to dienophile. In the sigmatropic rearrangement, the migration of the sigma bond takes place. Electrocyclic reactions involve the conversion of $\text{σ}$ bonds into $\text{π}$ bonds or $\text{π}$ bonds into $\text{σ}$ bonds.

Interpretation Introduction

(d)

Interpretation: The given reaction is to be classified as an electrocyclic reaction, cycloaddition, or a sigmatropic rearrangement. The sigma bonds that are broken or formed in the given reaction are to be labeled.

Concept introduction: A chemical reaction that involves $\left[4+2\right]$ cycloaddition is called Diels-Alder reaction. The reactant molecules that give rise to product are diene and dienophile. The rate of reaction is fast when the electronegative group is attached to dienophile. In the sigmatropic rearrangement, the migration of the sigma bond takes place. Electrocyclic reactions involve the conversion of $\text{σ}$ bonds into $\text{π}$ bonds or $\text{π}$ bonds into $\text{σ}$ bonds.