Course

Unit II

Aromaticity: Review of inductive and field effects Resonance effects. Criteria for aromaticity structural and electronic. Types Huckel and Craigs rule, homo (Five, Six, seven and eight, membered rings), hetero (furan, thiophene and pyrrole) and nonbenzenoid aromatic systems. Aromaticity of fused rings, annulenes, catenanes, rotaxanes, mesoionic compounds, metallocenes, cyclic carbocations and carbanions.

Unit III

Structure activity relationships Orientation effects of substituent, Quantitative treatment of structure on reactivity – free energy relationships Hammett equations, Taft equation.Reactive Intermediates: Generation, structure and reactivity – reactions and rearrangement involving) of carbocations – non-classical carbocations, carbanions, carbon radicals, radical ions, carbenes, nitrenes, isonitrenes, arynes.

Unit IV

Mechanism and methods to determining them: Thermodynamic and kinetic requirement, Baldwin rules for ring closure Kinetic and thermodynamic control Hammond postulates, microscopic reversibility, Marcus theory, methods of determining reaction mechanisms – solvents and their effect on course of a reaction. Acids and Bases: Bronsted and Lewis acids – HSAB concept and bases, pH and pKa, effect of structure on acidity and basicity, effect of medium.

Unit V

StereochemistryOptical and geometrical isomerism, absolute and relative configuration, Cahn-Ingold-Prelog system, prochirality, prochiral centre, atoms, groups and faces, designations. Atropisomerism, optical isomerism in biphenyls, allenes, spirans and ansa compounds, compounds containing chiral nitrogen and sulphur atom, geometrical isomerism of cyclic compounds, cumulenes and oximes. Asymmetric synthesis, stereospecific and stereoselective synthesis, regioselective and regiospecific reactions.

Conformational AnalysisConformational analysis of cyclic and acyclic systems with special emphasis on six membered rings, conformational effects on the reactivity of acyclic and cyclic systems – elimination, substitution and addition, strain, structure and stability of small, medium, and large rings, anomeric effect – cycloalkenes and cycloalkynes- kinetically and thermodynamically favoured products stereochemistry of SN1, SN2, SNi, E1 and E2Selectivity in organic reactions: Chemoselectivity, regioselectivity, enantio- and stereo-selectivity. Stereo aspects of the addition of X2, HX, boranes and hydroxylation to C=C systems. Cis- and trans- hydroxylation of cycloalkenes.

TEXT BOOKS1.Michael B Smith, March’s Advanced Organic Chemistry: Reactions, Mechanisms and Structure, 7th edition, Wiley (2015).2.Francis A. Carey and Richard J. Sundberg, Advanced Organic Chemistry – Part A: Structure and Mechanisms, 5th Edition, Springer, 20083.P. S. Kalsi, Stereochemistry, Conformation and Mechanism, New Age Publications, 2008.REFERENCES1.E. L. Eliel and S. H. Wilen, Stereochemistry in Organic Compounds, John Wiley, 2008.2.D. Nasipuri, Stereochemistry of Organic Compounds – Principles and Applications, 4th Revised Edition, New Academic Science, 2012.3.Peter Sykes, A Guidebook to Mechanism in Organic Chemistry, Pearson Education; 6th edition, 2003