Syllabus

Pericyclic reactions: Electrocyclic Reaction: Molecular orbitals and symmetry operations, Aromatic transition state approach (Huckel and Mobius systems), Woodward-Hoffmann rule, correlation diagrams, Frontier orbital theory. Electrocyclic reactions: Thermal and photochemical electrocyclic processes. Electrocyclic reactions of cations, anions, radicals and radicals ions, Nazarov cyclization, ring opening of aziridines Cycloaddition reactions: [4+2] cycloaddition reactions, nature of diene Orbital description,, dienophile, stereochemistry of product. Regioselectivity in Diels-Alder reactions, endo selectivity. Intramolecular Diels-Alder reaction. Retro-Diels-Alder reaction. Genaration and reactions of quinodimethanes, benzofurans. Photochemical and thermal [2+2]-cycloaddition reaction, Ketene cycloaddition, Alder ‘Ene Reaction’ Transition metal-catalyzed cycloadditions. 1,3-Dipolar cycloadditions application to heterocycle synthesis (Huisgen reaction, “Click” reaction). Cheletropic reactions. Sigmatropic reactions: Orbital description, [1,3], [1,5], [1,7], [2,3], [3,3] and [5,5] sigmatropic shifts, theory and reactions. Cope rearrangement, Oxy-cope rearrangement, Claisen rearrangement, Abnormal-claisen rearrangement, variants of Claisen rearrangement.
Photochemically driven organic reactions: Principles and concepts, Jablonski diagram and photophysical processes, Franck-Condon principle. Reactions: Photochemistry of alkene, di-pi-methane rearrangement. Photochemistry of carbonyl compounds, Norrish type-I and type-II reactions, Paterno-Buchi reaction, photochemistry of enone and dienones. Barton reaction, photo oxidation and reduction, photo-Fries rearrangement.

To provide an in-depth knowledge of concept of concerted reactions and their mechanisms, including the Woodward-Hoffmann rules and the concepts of allowed and forbidden reactions.

To understand and identify different types of pericyclic reactions, such as cycloadditions (e.g., Diels-Alder), electrocyclic reactions, and sigmatropic reactions.

To understand the basics of photochemical reactions, including the interaction of light with matter and the concept of excited states and different types of photochemical reactions, such as photoisomerization, photoreduction, and photooxidation.

To understand how pericyclic reactions and photochemical reactions can be used in organic synthesis to construct complex molecules.

CO1: Students will gain an in-depth knowledge of concept of concerted reactions and their mechanisms, including the Woodward-Hoffmann rules and the concepts of allowed and forbidden reactions.
CO2: Students will be able to identify different types of pericyclic reactions, such as cycloadditions (e.g., Diels-Alder), electrocyclic reactions, and sigmatropic reactions.
CO3: Students will gain an in-depth knowledge on organic photochemistry, including the interaction of light with matter and the concept of excited states and different types of photochemical reactions, such as photoisomerization, photoreduction, and photooxidation.
CO4: Students will understand how pericyclic reactions and photochemical reactions can be used in organic synthesis to construct complex molecules.
CO5: Students will be able to understand the difference in reactivity under thermal and photochemical conditions and devise methodology to synthesize regioselective and stereoselective products.

. R. B. Woodward and R. Hoffmann, The Conservation of Orbital Symmetry, Academic Press, New York

M. Smith, Organic Synthesis, Mc Graw Hill

R. P. Wayne, Principles and Applications of Photochemistry, Oxford Science Publications, Oxford University Press, Oxford

M. J. S. Dewar and R. C. Dougherty, The PMO Theory of Organic Chemistry, Plenum Press, New York