Chapter 24, Problem 24.6YT

Interpretation Introduction

Interpretation:

In the given Diels-Alder reaction, the C atoms in the product that have rehybridized from ${\text{sp}}^{\text{2}}$ to ${\text{ sp}}^{\text{3}}$, making them potential chiral centers in other Diels–Alder reactions, are to be identified.

Concept introduction:

The [$\text{4+2}$] cycloaddition reaction is generally known as Diels-Alder reaction. A Diels-Alder reaction involves a diene and a dienophile. A diene shares four π electrons from the two conjugated π bonds while a dienophile shares two π electrons from a single π bond. The Diels-Alder reaction is concerted and proceeds through a six-membered aromatic transition state. For a Diels-Alder reaction to occur, the diene must be present in the s-cis conformation because both ends of the diene must be relatively close to the dienophile in the transition state. In a standard Diels-Alder reaction, four carbon atoms are rehybridized from ${\text{sp}}^{\text{2}}$ to ${\text{ sp}}^{\text{3}}$: two from the dienophile and two from the diene. Due to this transformation, chiral centers may be introduced in the product.