Chapter 20, Problem 20.37P

Interpretation Introduction

Interpretation:

The structural formula of the product formed in the given Diels-Alder reaction, has to be drawn with stereochemistry.

Concept Introduction:

Diels-Alder reaction:

It is the reaction of conjugated dienes with double or triple bonded compounds which are known as “dienophiles”. The reaction is a $4+2$ cycloaddition reaction that results in the formation of a six membered cyclic product which is known as “adduct”.

Example:

This mechanism shown that three $\text{π}$-bonds are broken to form two new $\text{σ}$ -bonds and a new $\text{π}$-bond.

Stereochemistry in a product formed: In the product of a chemical reaction, if a carbon atom has been attached with four different carbon atoms, then it is known as chiral carbon atom or stereocenter in the product. The bond of the functional group because of which a new chiral carbon is supposed to form has to be represented in solid wedge bond.

Racemic mixture in Diels-alder reaction:

In the Diels-alder reaction, the formation of two new sigma bonds results in the formation of two new chiral centres that are enantiomers to each other. So, the Diels-alder adduct is the mixture of two enantiomers and therefore it is being a racemic Diels-alder adduct.