Diels-Alder Reaction-For the preparation of cyclohexene

Here is the detailed description of Diels Alder Reaction important for cyclohexadiene production at industrial level

2. DIELS ALDER REACTION

3. TABLE OF CONTENTS
INTRODUCTION
HISTORY
R*X EQUATION
MACHANISM
STEREOCHEMISTRY
APPLICATIONS
TABLE OF
CONTENTS

4. It is an organic reaction which is used to convert
conjugated dione (a molecule with two alternating double
bonds and a dienophile (alkene) to a cyclic olefin.
The reaction between 2,3 unsaturatedCarbonyl
compounds (dienophile) with conjugated dienes to form
addition product is called as Diel's Alder reaction.
INTRODUCTION OF REACTION
Definition
OR

5. This reaction was discovered by theGerman chemists
Otto Diels and Kurt Alder in the year 1928, for which they
received the Nobel Prize in Chemistry in the year 1950.
HISTORY OF REACTION
1950
OTTO DIELS KURT ALDER

6. Diels–Alder reactions can be reversible under certain
conditions; the reverse reaction is known as theretro-
Diels–Alder reaction.
The Diels–Alder reaction is particularly useful in synthetic
organic chemistry as a reliable method for forming 6-
membered systems with good control over regio- and
stereo chemical properties.The underlying concept has
also been applied to other π-systems, such
ascarbonylsandimines, to furnish the corresponding
heterocyclic, known as thehetero-Diels–Alder reaction.
REACTION EQUATION

7. REACTION EQUATION
Between a conjugateddiene and a substitutedalkene,
commonly termed the dienophile, to form a
substitutedcyclohexenesystem

8. Bonds
Formed
C1-C6
C2-C3(π)
C4-C5
Bonds
Broken
C1-C2(π)
C3-C4(π)
C5-C6(π)
REACTION EQUATION
‘

9. REACTION MECHANISM
Step:1
Formation Of a
“dimer”
The diene and the
dienophile combine to
form a six-membered
ring.
Step: 2
Cyclization
The six-membered
ring is converted
into a three-
membered ring.

10. The Diels-Alder reaction is favored by electrophilic
dienophiles with electron-withdrawing groups attached to
them.
It is also favored bynucleophilicdienes with electron-
donating groups in them.
The reaction proceeds in a single step cycloaddition
reaction.
One part is dine (which is comprised of two adjacent pi
bonds).
The other part is dienophile which is diene loving and has
at least one pi bond .
REACTION MECHANISM

11. REACTION MECHANISM
A conjugated diene reacts with a double-bonded dienophile

12. REACTION MECHANISM
Alpha 1,4 addition to 1,3 butadiene

13. Bonds
Formed
C1-C6
C2-C3(π)
C4-C5
Bonds
Broken
C1-C2(π)
C3-C4(π)
C5-C6(π)
REACTION MECHANISM
‘

14. REACTION MECHANISM
Normally, dienes are electron-rich; dienophiles are electron-poor

15. REACTION MECHANISM
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16. Stereo chemical information in the reactants is retained in
the products.
The Diels-Alder reaction is stereospecific.
Substituents that are cis (trans) on the dienophile will be
cis (trans) on the new six-membered ring.
The two substituents on the “outside” of the diene (in the s-
cis conformation) will end up cis on the new six-membered
ring, as will the two substituents on the “inside” of the
diene.
STEREOCHEMISTRY OF
DIELS-ALDER REACTION

17. E- andZ-dienophiles, give rise to the adducts
with correspondingsynoranti-stereochemistry.
STEREOCHEMISTRY OF
DIELS-ALDER REACTION
Example:

18. STEREOCHEMISTRY OF
DIELS-ALDER REACTION

19. The Diels-Alder reaction involves the shift of four pi
electrons of the diene and two pi electrons of the dienophile.
This reaction is used in the production of vitamin B6.
The reverse reaction (also called the retro-Diels-Alder
reaction) is used in the production of cyclopentadiene on an
industrial scale.
APPLICATIONS OF DIELS
ALDER REACTION
Production Of Vitamin B6

20. Reaction:

21. The Diels Alder reaction is commonly used in the
synthesis of six membered rings contained in steroids
such as cortisone.
Synthesis Of Cortisone:
Reaction:

22. Rule # 8
Asymmetric Diels-Alder reaction is one step in the
biosynthesis of the statin lovastatin.
Biosynthesis of Lovastatin:
Reaction:

23. Synthesis Of Prostaglandins:
Alder reactions were used in the original synthesis of
prostaglandins F2α and E2.
The Diels–Alder reaction establishes the relative
stereochemistry of three contiguous stereocenters on the
prostaglandin cyclopentane core.
Activation by Lewis acidic cupric tetrafluoroborate was
required

24. Reaction:
Synthesis Of Prostaglandins:

25. A synthesis of reserpine uses a Diels–Alder reaction to set
the cis-decalin framework of the D and E rings.
Synthesis Of Reserpine:
Reaction:

26. Synthesis of Tetracycline (Myers and Charest, 2005):
RECENT LITERATURE OF
REACTION METHOD
The research group of Andrew G. Myers of Harvard
University developed a platform for the synthesis of a
diverse range of tetracycline antibiotics which relies on
the Diels-Alder reaction.

27. Synthesis of Tetracycline (Myers and Charest, 2005):

28. What makes the Diels-Alder so useful?
Two things; First, it sets the stereochemistry at C-5
(numbered in RED – not IUPAC numbering).
Secondly, and by far more important, is that the Diels-Alder
allows one to join together two very complex fragments in a
very predictable way.
The beauty of the Diels-Alder strategy in the tetracycline
synthesis is that it is convergent; one can make a complex
diene and a complex dienophile and then bring them together
at a late stage.
Synthesis of Tetracycline (Myers and Charest, 2005):

29. Haloalkanes as Diels-Alder Dienophiles
APPLICATIONS TO
GENERATING USEFUL
STRUCTURAL PATTERNS
Audrey G. Ross, Steven D. Townsend and Samuel J. Danishefsky

30. References Of Recent Literature:
Link; https://pubs.acs.org/doi/10.1021/ja052151d
Email: [email protected]
Citation; Mark G Charest 1, Dionicio R Siegel, Andrew
G Myers, 2005
Department of Chemistry, Columbia University,
Havemeyer Hall, 3000 Broadway, New York, New York
10027, United States