This document summarizes Sameer Hussain's thesis project on the construction of carbon-carbon bonds via photogenerated intermediates under the supervision of Prof. Ravi P. Singh. It introduces various photochemical and photocatalytic methods for carbon-carbon bond formation using reactive intermediates like radicals, carbenes, and biradicals generated with photoredox catalysts like eosin Y and ruthenium complexes under visible light. Several examples of aryl-carbon bond formation via ipso substitution and cross-coupling reactions conducted with high yields between 68-92% are summarized. The document concludes by anticipating broad applications of these photoredox reactions and discussing future research perspectives in the field.

1. CMD631 (Semester I, 2020-2021)
Project Submitted by
Sameer Hussain
2019CYS7042
Thesis supervisor
Prof. Ravi P. Singh
Department of Chemistry
Indian Institute of Technology, Delhi
New Delhi 110016
Construction of Carbon-Carbon(Ar-C) Bond via
Photogenerated Intermediates

2. INTRODUCTION
1. Carbon-Carbon bond formation via various photochemical and
photocatalytic methods.
2. Photochemical generated intermediates; aryl radicals, benzyl radicals,
simple radicals and carbenes
3. Photoredox catalysts like Eosin Y, Ru(bpy)2+, Cu(dpp)2
+ by activating in
the presence of visible light.
4. Ar-C bond formation by ipso substitution of various functional groups.

3. Photoredox catalysts
Fig. 1. Commonly used photoredox catalysts

4. Mechanism of photoredox reaction
Fig. 2. General mechanism of photoredox catalyst

5. 1. Visible-Light-Mediated Direct C−H Arylation of
Heteroarenes with Aryl Diazonium Salts.
21-80%

6. 2. Homolytic aromatic substitutions via photoredox
catalysis to assemble biaryls

7. 3. Oxyarylation and Aminoarylation of Styrenes
Using Photoredox Catalysis

8. 4. Intermolecular Formyloxyarylation of Alkenes
by Photoredox Meerwein Reaction

9. 5. Visible-light-mediated oxidative arylation of
vinylarenes under aerobic conditions

10. 6. Aryl Radical formation by Cu(I) for
photocatalyzed reduction of diaryliodonium salts.
75-80%

11. 7. Photocatalyzed transformation of
heteroarenes into aryl ketones

12. 8. Radical Alkoxycarbonylation of Aryldiazonium
Salts through Visible-Light Photoredox Catalysis.

13. 9. Photoredox Cross-Coupling Ir/Ni Dual
Catalysis for the Synthesis of Benzylic Ethers.
70-92%

14. 10. A visible-light mediated three-component radical
process using dithiocarbamate anion catalysis.
28-72%

15. 11. Organocatalytic Activation of C−H Bonds via
Photoredox Catalysis; Direct Arylation of Benzylic Ethers.
68-72%

16. 12. Decarboxylative Arylation of α-Amino Acids
via Photo Redox Catalysis.
80-82%

17. Summary
Starting with the importance and application of photochemical reactions we
introduced the generation of reactive intermediates like radicals, biradicals,
radical ions, cations & anions and carbenes in the presence of photoredox
catalysts like eosin Y, rose Bengal and other Ir & Ru based catalysts,
irradiating via visible light of different intensities and also sometimes UV
light. We proceeded with Ar-C bond formation via ipso substitution of
various functional groups.
From discussion we anticipate these photoredox or photochemical reactions
will find broad applications among practitioners of organic synthesis.

18. Future perspectives
79 20
80

19. Acknowledgement
Dr. Ravi P. Singh ( Principal Investigator)
Sanjay Singh(Phd)
Department of Chemistry
IIT Delhi, New Delhi

20. References
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