Chapter 13, Problem 11PP

Interpretation Introduction

Interpretation:

The transition states of exo and endo Diels Ander reactions of maleic anhydride with cyclopentadiene are to be drawn. Also, the transition state that leads to only one enantiomer need to be shown in each.

Concept introduction:

A Diels Ander reaction is one between a conjugate diene and a reactant containing a double bond (dienophile) to form a product. The product is called adduct.

Diels Ander reactions are highly stereospecific. The configuration of the dienophile is retained in the product and the reaction is a syn addition reaction.

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

Endo and exo refer to the orientation of the dienophile and its electron-withdrawing group when it reacts with a diene in a Diels Ander reaction.

Endo is favored in the transition state of a Diels Ander reaction because it has a lower energy.