Chapter 16.7, Problem 18CC

(a)

Interpretation Introduction

Interpretation:

The major product for the given reaction has to be determined.

Concept introduction:

• Cycloaddition reaction is a concerted addition reaction of two reactants to form a ring; in which two π-bonds are converted to two σ-bonds.
• Diels-Alder reaction is a $\left[\text{4+2}\right]\text{ cycloaddition}$ reaction between a diene and a dienophile producing a substituted cyclohexene.
• The mechanism of the ring formation in the Diels-Alder reaction is drawn by using three arrows representing the shifting of π-bonds in the two π-systems in a clockwise or counter clockwise fashion, so that the ring formation will take place.
• The configuration of dienophile will be retaining in the product.

Regiochemistry in Diels-Alder reaction:

While forming the product in the Diels Alder reaction, the strongest electron withdrawing group on the dienophile and the strongest electron donating group on the diene will be either $\text{1,2}\text{or}\text{1,4}$ disubstituted.

(b)

Interpretation Introduction

Interpretation:

The major product for the given reaction has to be determined.

Concept introduction:

• Cycloaddition reaction is a concerted addition reaction of two reactants to form a ring; in which two π-bonds are converted to two σ-bonds.
• Diels-Alder reaction is a $\left[\text{4+2}\right]\text{ cycloaddition}$ reaction between a diene and a dienophile producing a substituted cyclohexene.
• The mechanism of the ring formation in the Diels-Alder reaction is drawn by using three arrows representing the shifting of π-bonds in the two π-systems in a clockwise or counter clockwise fashion, so that the ring formation will take place.
• The configuration of dienophile will be retaining in the product.

(c)

Interpretation Introduction

Interpretation:

The major product for the given reaction has to be determined.

Concept introduction:

• Cycloaddition reaction is a concerted addition reaction of two reactants to form a ring; in which two π-bonds are converted to two σ-bonds.
• Diels-Alder reaction is a $\left[\text{4+2}\right]\text{ cycloaddition}$ reaction between a diene and a dienophile producing a substituted cyclohexene.
• The mechanism of the ring formation in the Diels-Alder reaction is drawn by using three arrows representing the shifting of π-bonds in the two π-systems in a clockwise or counter clockwise fashion, so that the ring formation will take place.
• The configuration of dienophile will be retaining in the product.
• Endo-product is the major product in bicyclic-products of Diels-Alder reaction; because the electron-withdrawing substituents of dienophile and the newly forming π-bond of diene are interacted each other.

(d)

Interpretation Introduction

Interpretation:

The major product for the given reaction has to be determined.

Concept introduction:

• Cycloaddition reaction is a concerted addition reaction of two reactants to form a ring; in which two π-bonds are converted to two σ-bonds.
• Diels-Alder reaction is a $\left[\text{4+2}\right]\text{ cycloaddition}$ reaction between a diene and a dienophile producing a substituted cyclohexene.
• The mechanism of the ring formation in the Diels-Alder reaction is drawn by using three arrows representing the shifting of π-bonds in the two π-systems in a clockwise or counter clockwise fashion, so that the ring formation will take place.
• The configuration of dienophile will be retaining in the product.

(e)

Interpretation Introduction

Interpretation:

The major product for the given reaction has to be determined.

Concept introduction:

• Cycloaddition reaction is a concerted addition reaction of two reactants to form a ring; in which two π-bonds are converted to two σ-bonds.
• Diels-Alder reaction is a $\left[\text{4+2}\right]\text{ cycloaddition}$ reaction between a diene and a dienophile producing a substituted cyclohexene.
• The mechanism of the ring formation in the Diels-Alder reaction is drawn by using three arrows representing the shifting of π-bonds in the two π-systems in a clockwise or counter clockwise fashion, so that the ring formation will take place.
• The configuration of dienophile will be retaining in the product.