A Study Guide in Organic Retrosynthesis: Problem Solving Approach

By Prof. Samik Nanda   |   IIT Kharagpur
Learners enrolled: 2598

Organic synthesis of small molecules is the most challenging and intriguing area of research in the chemical science related disciplines. In the early 20th century, the field of synthetic organic chemistry, while established in many respects, was to continue a sharp path of progress and advancement for over a century to reach the level of power and sophistication that it possesses today. This is a unique tool for accessing new chemical entities with great biological potential, which seems to be impossible to access from natural sources due to its scarce availability. In this coursework I will try to address various aspects of organic synthesis through a problem/puzzle solving approaches so that students can learn in an interactive manner and excel in competitive exams.

INTENDED AUDIENCE: Chemistry, Medicinal Chemistry

PREREQUISITES: Basic Organic Chemistry, Stereochemistry

INDUSTRY SUPPORT: Pharmaceutical Industry
Course Status : Completed
Course Type : Core
Duration : 12 weeks
Category :
  • Chemistry
Credit Points : 3
Level : Undergraduate/Postgraduate
Start Date : 24 Jan 2022
End Date : 15 Apr 2022
Enrollment Ends : 07 Feb 2022
Exam Date : 23 Apr 2022 IST

Note: This exam date is subjected to change based on seat availability. You can check final exam date on your hall ticket.

Page Visits

Course layout

Week 1: Introductory remarks: Why to study organic synthesis? Historical perspectives of organic synthesis.
Establishing a visual dialogue with the target molecules (imagination, creativity and execution).
Week 2: Retrosynthetic disconnections: The basis for retrosynthetic analysis and terminologies,
Transform based strategies, Substrate/precursor based strategies.
Week 3: Retrosynthetic disconnections: Functional group based strategy
(concept of redundant functionality) and mechanism based strategy (including biomimetic pathways)
Week 4: Retrosynthetic disconnections: Consideration of symmetry elements in synthetic planning;
Local symmetry and pseudo symmetry. Synthesis of symmetrical molecules and concoctive species.
Week 5: Retrosynthetic disconnections: Stereochemical strategies Strategies to create new chiral center/s in a organic molecule
(Resolution, Desymmetrization, Substrate directed approach, Chiron approach, Absolute asymmetric synthesis)
Week 6: Retrosynthetic disconnections: Enantiodivergent and enantioconvergent approaches and case studies (meso trick and C2-trick).
Week 7: Synthetic equivalents: Concepts of synthetic equivalents (formyl/acyl anion, enolate, homoenolate,
Conjunctive species, Linchpin strategy and other related species) and its application in total synthesis.
Week 8: Fragmentation reactions (Overbred intermediates) and molecular rearrangements and its application in organic synthesis
Week 9: Stereochemistry and conformational analysis: Concepts and application of A1,2/A1,3 strain. Baldwin’s cyclization rule.
Week 10: Protecting groups: Selective protection and deprotection of various functional groups and its application in total synthesis
Week 11:Few important name reactions and their applications in organic synthesis
(Several name reactions based on Substitution/displacement strategy, Reductive strategy,
Oxidative strategy, Coupling reactions, Cyclization reactions
Week 12: Total synthesis of few natural products: Longifolene (Corey/ Oppolzer);
Isocomene (Pirrung); Hirsutene and Δ9(12) Capnellene (Curran), Taxol (Nicolaou); Epothiolone A & B (Nicolaou).

Books and references

1. The Logic of Chemical Synthesis by E. J. Corey and X.M. Cheng
2. Organic synthesis: Strategy and Control; by Paul Wyatt and Stuart warren
3. Modern Organic Synthesis: G. S. Zweifel, M. H. Nantz and P. Somfai
4. www.synarchive.com (for a list of name reactions and other details)
5. Strategic Applications of named Reactions in Organic Synthesis: L. Kurti and B. Czako

Instructor bio

Prof. Samik Nanda

IIT Kharagpur
Samik Nanda after finishing my PhD in the field of “asymmetric synthesis with the help of enzymes” I was very much interested to carry out an independent research career in the field of asymmetric total synthesis of natural products. Since last ten years the research focus of my group was focused on the central theme of “asymmetric synthesis”. We tried to explore many well developed asymmetric synthesis protocols to access our desired target molecules. We have also developed few in-house evolved asymmetric processes which were also successfully employed to access many enantiopure small organic molecules.

Course certificate

The course is free to enroll and learn from. But if you want a certificate, you have to register and write the proctored exam conducted by us in person at any of the designated exam centres.
The exam is optional for a fee of Rs 1000/- (Rupees one thousand only).
Date and Time of Exams: 23 April 2022 Morning session 9am to 12 noon; Afternoon Session 2pm to 5pm.
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. If there are any changes, it will be mentioned then.
Please check the form for more details on the cities where the exams will be held, the conditions you agree to when you fill the form etc.


Average assignment score = 25% of average of best 8 assignments out of the total 12 assignments given in the course.
Exam score = 75% of the proctored certification exam score out of 100

Final score = Average assignment score + Exam score

YOU WILL BE ELIGIBLE FOR A CERTIFICATE ONLY IF AVERAGE ASSIGNMENT SCORE >=10/25 AND EXAM SCORE >= 30/75. If one of the 2 criteria is not met, you will not get the certificate even if the Final score >= 40/100.

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 Kharagpur .It will be e-verifiable at nptel.ac.in/noc.

Only the e-certificate will be made available. Hard copies will not be dispatched.

Once again, thanks for your interest in our online courses and certification. Happy learning.

- NPTEL team

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