Nomenclature of benzene derivatives (mono and disubstituted), physical properties. Introduction to aromatic compounds: Benzene, structure and stability, M.O concept, resonance and resonance energy; Aromaticity, Huckel’s rule with cyclic carbocations/carbanions and heterocyclic compounds, annulenes & kekulene as examples, elementary idea of aromatic, antiaromatic and homoaromatic compounds. Pseudoasymmetry.
Aromatic electrophilic substitution – general pattern of the mechanism, s and p complexes, energy profile diagram, activating and deactivating effects of substituents, orientation, o/p ratio, halogenation, nitration, sulphonation and desulphonation, friedel crafts alkylation and acylation; side chain halogenation of alkyl benzenes (toluene, ethyl benzene), Birch reduction, One carbon electrophiles reactions: chloromethylation, Gatterman-Koch, Gatterman, Hoesch, Vilsmeier-Haack reaction, Reimer-Tiemann, Kolbe-Schmidt.
General preparation and reactions of alkyl halides, Substitution at sp3 centre - Mechanism: SN1, SN2, SNi mechanisms with stereochemical aspects, effect of solvent, substrate structure, leaving group, nucleophiles including ambident nucleophiles (cyanide & nitrite) substitution involving NGP
Aryl halides: Preparation, nucleophilic aromatic substitution; Benzyne mechanism, relative reactivity of alkyl, allyl, benzyl, vinyl and aryl halides towards nucleophilic substitution reactions.
Newman, Fischer, Sawhorse and Flying-wedge formula; conformation of ethane, n-butane and cyclohexane – axial and equitorial bonds, conformational analysis of monosubstituted and disubstituted cyclohexane (dimethyl cylcohexane), concepts of conformational locking; chair conformation of α and β glucose and their stability.