Chapter 13, Problem 44P

Interpretation Introduction

Interpretation:

The diene and dienophile for the given products are to be determined.

Concept introduction:

Diels–Alder is a type of organic reaction in which substituted alkene and conjugated diene react to form substituted cyclohexene derivative. It is a single step reaction.

The general reaction of Diels–Alder is as follows:

Diels–Alder reaction is between a conjugate diene and a reactant containing double bond (dienophile) to form the product and the product is called adduct.

Diels–Alder reactions are highly stereospecific. The configuration, if dienophile is retained in the product and the reaction, is syn addition.

The dienes react with dienophiles in cis forms rather than trans forms.

Endo and exo refers to the orientation of dienophile and its electron withdrawing group, when it reacts with a diene in Diels–Alder reaction.

The reaction with orientation of electron withdrawing group of dienophiles under the $\pi$ orbitals of the diene is endo.

The reaction with orientation of electron withdrawing group of dienophiles away from the $\pi$ orbitals of the diene is exo

Endo is favored in the transition state of Diels–Alder reaction because of its lower energy.

If a compound is stable, it has lower energy and if a compound is unstable, it has higher energy.