Courses » Pericyclic Reactions and Organic Photochemistry

Pericyclic Reactions and Organic Photochemistry


The aim of the course is to make students familiar with the concepts and applications in two important topics in advanced organic chemistry, namely concerted organic reactions and organic photochemistry.

Pericyclic reactions are concerted organic reactions and are governed by Woodward-Hoffmann rules. Different methods of analysis of pericyclic reactions to arrive at the Woodward-Hoffmann rules will be presented. Synthetic applications and mechanisms of various pericyclic reactions will be discussed. Similarly the concepts involved in understanding organic photochemical reactions, their mechansims and applications in organic synthesis will be presented.
This course will uncover all the major topics in pericyclic reactions and organic photochemistry.  In addition to lectures there will be tutorial sessions and assignments in this course.

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Weekly Assignments and Discussion Forum can be accessed ONLY by enrolling here

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All content including discussion forum and assignments, is free

Final Exam (in-person, invigilated, currently conducted in India) is mandatory for Certification and has INR Rs. 1100 as exam fee

  • Core for post-graduates
  • Post-graduate and upper level undergraduate
  • Final Year BSc, MSc and PhD


Basic course in organic chemistry, stereochemistry and reaction mechanisms


  • Pharma and fine chemical industry R&D labs
  • National labs such as NCL, IICT etc


Prof. S. Sankararaman
has 25 years of teaching and research experience at IIT Madras He teaches theory courses on organic chemistry, organometallic chemistry, spectroscopy and photochemistry to MSc and PhD students in addition to teaching basic organic and inorganic chemistry courses to B.Tech students. He has written a textbook on Pericyclic Reactions published by Wiley-VCH in 2005.  His research interests are in the areas of organic and organometallic chemistry, organic synthesis and catalysis.



General introduction to the course, activation of chemical reactions.  thermal and photochemical methods, molecular orbitals of conjugated polyenes and their symmetry properties, definition and classification of pericyclic reactions
methods of analyzing pericyclic reactions.

Week 2:

Electrocyclic reactions – introduction, definition and classification, Woodward- Hoffmann rules for electrocyclic reactions, Stereochemical aspects and modes of electrocyclic reactions, analysis of electrocyclic reactions by various methods, examples of electrocyclic reactions.

Week 3:

Electrocyclic (continued), Cycloaddition reactions, Woodward- Hoffmann rules for cycloaddition reactions, stereochemical aspects and modes of cycloaddition reactions, analysis of cycloaddition reactions by various methods

Week 4:  

Examples of thermal and photochemical [2p+2p] cycloaddition reactions
Synthesis of cage type compounds using [2p+2p] cycloaddition reactions
Diels-Alder reaction and its variants and their syntic utility

Week 5: 

1,3-Dipolar cycloaddition reactions, higher order cycloaddition reactions, sigmatropic rearrangements, Woodward Hoffmann rules for sigmatropic rearrangements

Week 6:

Sigmatropic rearrangements – examples, Claisen and Cope rearrangements
[2,3]-sigmatropic rearrangements and higher order rearrangements
Chelotropic reactions - introduction, definition and classification, Ene reaction.

Week 7:     

Organic photochemistry – introduction, definitions, importance
Electronic excitation and spin configurations – Jabolanski diagram
Energy transfer and electron transfer processes – quenching of excited states
Photochemistry of carbonyl compounds

Week 8:

Photochemistry of olefins, enones and dienones, photochemistry of aromatic molecules, molecular oxygen and organic photochemistry, supramolecular organic photochemistry.

Reference Books:

1. S. Sankararaman, Pericyclic Reactions – A textbook.  Wiley-VCH, 2005.

2. I. Fleming, Pericyclic Reactions, Oxford University Press, 1999.

3. N. J. Turro, V. Ramamurthy and J. C. Scaiano, Modern molecular photochemistry of organic compounds, University Science Books, 2010.

  • The exam is optional for a fee.
  • Date of Exams : October 28 (Sunday)
  • Time of Exams : Morning session 9am to 12 noon; Afternoon session: 2pm to 5pm
  • Exam for this course will be available in both morning & afternoon sessions.
  • Registration url: Announcements will be made when the registration form is open for registrations.
  • The online registration form has to be filled and the certification exam fee needs to be paid. More details will be made available when the exam registration form is published.


  • Final score will be calculated as : 25% assignment score + 75% final exam score
  • 25% assignment score is calculated as 25% of average of  Best 6 out of 8 assignments
  • E-Certificate will be given to those who register and write the exam and score greater than or equal to 40% final score. Certificate will have your name, photograph and the score in the final exam with the breakup.It will have the logos of NPTEL and IIT Madras.It will be e-verifiable at nptel.ac.in/noc.