The document summarizes the Diels-Alder reaction, a pericyclic reaction that involves the [4+2] cycloaddition of a diene (a compound with two double bonds) and a dienophile (an electron-deficient alkene). It occurs in a single step via a concerted mechanism without intermediates. The reaction requires heat or light activation and proceeds through a transition state with six delocalized pi electrons. Dienes with electron-donating groups or in the s-cis conformation react more readily, as do dienophiles with electron-withdrawing groups. An example reaction shown is the Diels-Alder reaction of buta-1,3-diene and

1. Diels Alder Reaction
Central
University
of Jammu
Date: 09 December, 2021
Zuhaib Nasir Mughal 4040319
Department of Chemistry
and Chemical Sciences.

2. Introduction
2

3. Diels alder reaction is a Pericyclic reaction
1
•This reaction will be something different, here we will neither ionic nor radica
• Source of activation energy will be either heat or light.
• There will be no intermediate formation.
• Dials alder reaction is a single step reaction.
• Mechanism of this reaction will be explained on the basis of Frontier molecula
3

4. Diels-Alder reaction
Otto Paul diels Kurt alder
4

5. It is a two components reaction;
Diene; the diene component of this reaction can be open chain or cyclic or it can
have many different kinds of substitutions. The only limitation is that it must be
able to take up the confirmation shown in the mechanism that is s-cis
confirmation. For example
2
S-cis form of diene are more reactive.
Cis
More reactive
Trans
Less reactive 5

6. Dienophile; dienophiles are the alkenes conjugated with a electron-
withdrawing group.There must be some extra conjugation—at least a
phenyl group or a chlorine atom—or the cycle additiondoes not occur.
As we often see the reaction between butadiene and simple alkene as the basic
Diels-Alder reaction, but this occur in very poor yield
6

7. Diene having electron donating group are more reactive and act as HOMO.
Dienophile having electron withdrawing group or more reactive and act as LOM
7

8. Mechanism;
As this reaction is a one step reaction there is no intermediate but there is one tra
Let diene be buta-1,3-diene and dienophile be malice anhydride.
3
8

9. Concerted mechanism;
Transition state has 6 delocalised
pi electrons
Heat
4
9
Diels-Alder reaction take place in presence of Heat

10. ?
10

11. Special thanks to Dr. Tapta Kanchan Roy (sir)
Linkedin.com/ZuhaibNasir
Slideshare.net/ZuhaibNasir
6
7
11