The 1,3-dipolar cycloaddition is a chemical reaction between a 1,3-dipole and a dipolarophile to form a five-membered ring. The earliest 1,3-dipolar cycloadditions were described in the late 19th century to the early 20th century, following the discovery of 1,3-dipoles. Mechanistic investigation and synthetic application were established in the 1960s, primarily through the work of Rolf Huisgen.[1] Hence, the reaction is sometimes referred to as the Huisgen cycloaddition (this term is often used to specifically describe the 1,3-dipolar cycloaddition between an organic azide and an alkyne to generate 1,2,3-triazole). 1,3-dipolar cycloaddition is an important route to the regio- and stereoselective synthesis of five-membered heterocycles and their ring-opened acyclic derivatives. The dipolarophile is typically an alkene or alkyne, but can be other pi systems. When the dipolarophile is an alkyne, aromatic rings are generally produced.

1. Submitted by Gobind Kumar
1,3dipolar
cycloaddtion
reactions
IK Gujral Punjab Technical University
PHD COURSE WORK
PRESENTATION

2. • Introduction
• Problem
• Literary Review
• Theoretical Framework
• Objectives
• Hypothesis
• Methodology
• Implementation
• Results
• Analysis
• Conclusion
• Recommendations
• References
MAJOR SECTIONS OF THIS
THESIS DEFENSE PRESENTATION
Overview

3. 1,3 dipolar Cycloadditions
* [(2π + 2e) + 2π] 1,3-dipolar cycloaddition is a reaction where two
organic compounds, a dipolarophile, and a 1,3-dipole (or ylide),
combine to form a five membered heterocycle.

4. 1,3 dipolar Cycloadditions
*This reaction is also referred to as the Huisgen cycloaddition. describe the 1,3-
dipolar cycloaddition between an organic azide and an alkyne to generate 1,2,3-
triazole.
* [(2π + 2e) + 2π] 1,3-dipolar cycloaddition is a reaction where two organic
compounds, a dipolarophile, and a 1,3-dipole (or ylide), combine to form a five
membered heterocycle.

5. 1,3 dipolarcycloaddition
Vs
Diels alder reaction
01 02
*in 1,3 dipolar cycloaddition
reaction a five membered ring is
formed as a end product.
*in diels alder reaction a six
membered ring is formed
as a end product.
*4π system = 1,3 dipole.
*2π system (alkene) = dipolarophile.
*4π system =
diene.
*2π system (alkene) = dienophile.

6. 1,3 dipole
*1,3-dipole is a dipolar compound with delocalized electrons and a separation
of charge over three atoms.

7. 1,3 dipole (two types)
01 02
Allyl anion Allenyl/propargyl anion

8. 1,3 dipole
vs
dienes
01 02
*1,3 dipole act as both
nucleophile as well as
electrohile.
*in FMO approach- act as
both HOMO as well as
LUMO.
*Dienes act as only
nucleophile.
*In FMO approach- act
as HOMO.

9. Dipolarophile
*dipolarphile- Simple alkene.
*Electron deficient alkene- act as excellent dipolarophile as well
as dienophile.
*α,βunsaturated aldehydes, ketones, and esters, allylic alcohols,
allylic halides, vinylic ethers and alkynes are examples of dipolarophiles
that react readily.

10. Classification of 1,3 dipolar
cycloadditon rxn on the basis
of FMO theory
HOMO-controlled
dipole
or
Nucleophilic
dipole
HOMO-LUMO
controlled dipole
or
Ambhiphilic
dipole
LUMO-controlled
dipole
or
Electrophilic
dipole
Type-I Type-II
Type-III

11. Type-I
*1,3 dipole act as
nucleophile (HOMO).
*dipolarophile act as
electrophile (LUMO)
*electron Poor alkene
required for this
interactions.

12. Type-I
(LUMO
)
(HOMO)

13. Type-I

14. Type-II
*1,3 dipole act as
electrophile (LUMO).
*dipolarophile act as
nucleophile (HOMO)
*electron Rich alkene
required for this
interactions.

15. Type-II

16. Type-II
(LUMO) (HOMO)

17. Type-III
*1,3 dipole act as
nucleophile (HUMO) or
electrophile (LUMO).
*dipolarophile act as
electrophile (LUMO) or
nuclieophile (HOMO).

18. Effect of Lewis Acid

19. HOMO-LUMO Interaction
*suprafacial
mode of
interaction
allow.

20. Stereospecificity
*Retention of configuration with respect to both the 1,3-
dipole and the dipolarophile.

21. Regioselectivity
*For asymmetric dipole-dipolarophile pairs, two
regioisomeric products are possible.
Electronic
effect
sterric
effect
*Two type of effect

22. Electronic effect

23. Sterric effect

24. Problem
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01 02

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26. 1
2
Literary Review
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27. Literary Review
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28. Overview
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Theoretical
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Proponents
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30. Hypothesis
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33. 2 out 5
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Results
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34. Item 1 Item 2 Item 3 Item 4 Item 5
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35. Item 1 Item 2 Item 3 Item 4 Item 5
40
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Harlow Research, January 2025
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with graphs and charts. These are visual aids
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discussing.

36. Item 1
20%
Item 2
20%
Item 3
20%
Item 4
20%
Item 5
20%
Results
Supported by data from Beal
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Conclusion

39. Recommendations
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40. References
Natural Science Edition 1 by D.B. Stanley (Book)
01
The Circle of Life by Sari Purdue (Article)
02
Our Great Ancestors by Elliot Sterling (Article)
03
Our World by Beal and Harlow Productions (Video)
04
The Great Evolution by Keel and Briar Group (Research Paper)
05

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