Advanced Organic Chemistry - Reactions And Mechanism

Discover how chain isomerism creates different carbon skeletons in alkanes, from normal butane to isobutane. Learn how pentane has three structural isomers and how increasing carbon count increases possible isomers.

Explore positional isomerism, where compounds share the same carbon skeleton but differ in the position of functional groups, double bonds, or substituents, with examples in alkanes, alkenes, and cyclic structures.

Explore functional isomerism, where compounds share the same formula but differ in functional groups, such as alcohols and aldehydes, yielding distinct properties.

Metamerism describes compounds with the same molecular formula and a common functional group, yet different alkyl groups around that group create distinct metamers, as shown by oxygen-centered examples.

Explore keto-enol tautomerism as a dynamic equilibrium between keto and enol forms, driven by hydrogen shifts from the alpha carbon to the carbonyl oxygen.

Explore conformational isomerism by examining staggered and eclipsed carbon-carbon single bonds, energy differences, and how rotation reveals stability of conformations.

Explore conformational isomerism in butane and propane by examining eclipsed, staggered, and gauche arrangements using Newman projections and sawhorse models; identify anti confirmation as stable and eclipsed as least stable.

Explore geometrical isomerism in alkenes by examining how restricted rotation around carbon–carbon double bonds produces cis and trans isomers, requiring different substituents on each carbon or cyclic locking.

Apply priority rules to alkenes, assign priority groups on each carbon of the double bond, and decide if they are on the same side (Z) or opposite (E).

Explore chirality by examining carbon centers with four different groups, yielding non-superimposable mirror images (enantiomers); contrast chiral versus achiral molecules with plane of symmetry and meso cases.

Explain how optically active chiral compounds rotate the plane polarized light, measured by a polarimeter, with dextro and levo forms, while optically inactive compounds lack rotation.

Learn absolute configuration by applying CIP rules to assign priorities, then determine R or S by clockwise or anticlockwise movement from 1 to 2 to 3, without reference compounds.

Identify aromatic, antiaromatic, and nonaromatic compounds by applying Huckel's rule (4n+2 electrons) to cyclic, planar, fully conjugated systems.

Classifies aromatic compounds into three main categories: benzenoid compounds, non-benzenoid aromatics, and other aromatic systems, highlighting fused benzene rings like naphthalene and azulene within conjugated structures.

Explore electrophilic aromatic substitution mechanisms on benzene, featuring resonance-stabilized intermediates, attachment of an electrophile, and hydrogen loss to restore aromaticity.

Explore halogenation and nitration of benzene through electrophilic aromatic substitution, forming halogenated or nitro derivatives via reaction intermediates, with sulfuric and nitric acids as catalysts.

Explains electrophilic addition to alkenes, detailing a two-step mechanism where an electrophile adds to the alkene, forms a carbocation intermediate, and a nucleophile attacks, with Markovnikov regioselectivity governing the major product.

Demonstrate how carbocation rearrangement occurs in electrophilic addition, driven by hydride shifts that create more stable secondary or tertiary carbons and yield the major product.

Explore the peroxide effect on alkene hydrogen addition, detailing anti-Markovnikov outcomes in the presence of peroxides versus Markovnikov outcomes without peroxides via radical mechanisms.

Explore hydration of alkenes: acid-catalyzed electrophilic addition of water to double bonds, Markovnikov selectivity, carbocation intermediates, hydride shifts, and formation of alcohols.

Demonstrates how halogens add to alkenes across the double bond, forming a cyclic intermediate and yielding anti addition products as bromide attacks from the opposite face.

Explore how hydrogenation of alkenes adds hydrogen to double bonds and how substitution and resonance influence stability, as reflected in the heat of hydrogenation.

Explains halohydrin formation: bromine adds to an alkene in water via a bromonium ion, water attack, deprotonation, yielding anti addition of bromine and hydroxyl.

Learn how alkenes undergo epoxidation with peroxide to form epoxides, followed by anti-dihydroxylation and acid-mediated hydrolysis to yield diols.

this lecture explains halohydrin formation from alkenes using bromine in water, detailing the cyclic intermediate and bromine addition with hydroxyl to the more substituted carbon.

Explore the addition of hydrogen and bromine to alkenes through practice problems, highlighting Markovnikov vs anti-Markovnikov outcomes with and without peroxides, and bromohydrin formation in aqueous bromination.

Explore reductive ozonolysis of alkenes, where ozone cleaves the carbon–carbon double bond to give ozonides that are reduced by dimethyl sulfide or zinc to aldehydes and/or ketones.

The lecture explains electrophilic aromatic substitution directing effects: electron-donating groups direct to ortho and para positions, while electron-withdrawing groups direct to the meta position, with phenol as an example.

Explore how electron-donating groups with lone pairs activate benzene via plus resonance, directing electrophilic aromatic substitution to ortho and para positions, with halogens as notable exceptions.

meta directing groups withdraw electrons from the benzene ring, creating a positive charge that directs substitution to the meta position; nitro and other ring deactivating groups slow reactivity.

This lecture explains how electron releasing groups activate benzene toward electrophilic aromatic substitution, while electron withdrawing groups deactivate it, noting halogens as exceptions and the para-major, ortho-minor directing pattern.

Learn how electrophilic attack on disubstituted benzenes follows directing effects, where a more powerful activating group governs the attack position, and deactivating groups influence outcomes.

Explains preparing aldehydes and ketones by oxidation of primary and secondary alcohols using mild reagents like PCC and PDC, avoiding strong oxidants that form carboxylic acids.

Explore methods to prepare aldehydes and ketones from nitriles, including reduction and hydrolysis steps, ammonia loss, and two-step pathways to ketones.

Reduce acid chlorides to aldehydes with hydrogen gas and a poisoned nickel catalyst. To obtain ketones, use dialkylcadmium reagents that replace the acyl chloride.

Learn the two-step ozonolysis of alkenes to form aldehydes and ketones by reacting with ozone, then reducing with zinc and water.

Explore how aldehydes and ketones, carbonyl compounds, exhibit resonance and sp2 hybridization, and how their boiling points and water solubility decrease with increasing carbon atoms due to hydrogen bonding.

Demonstrates how nucleophiles attack the carbonyl carbon in aldehydes and ketones, forms a tetrahedral intermediate with resonance to oxygen, and explains how substituents influence reactivity and reaction rates.

The lecture explains how Grignard reagents add to aldehydes and ketones to form alcohols after acidic hydrolysis, yielding primary, secondary, or tertiary alcohols depending on the carbonyl substrate.

In alkaline medium, water adds to aldehydes and ketones via a two-step mechanism to form hydrates, with rate increasing for less substituted carbonyls and formaldehyde, slowing with greater substitution.

Explore acetal formation from aldehydes and ketones with alcohols, detailing the mechanism from hemiacetal to acetal, acid catalysis, and using acetals as protecting groups in synthesis.

Explore how aldehydes oxidize to carboxylic acids easily, while ketones require strong oxidizing agents; learn Tollens' silver mirror test and Fehling's solution to distinguish them.

Explains how aldehydes and ketones can be reduced to alcohols or alkanes using reagents like hydrogen with nickel, lithium aluminum hydride, and Clemmensen and Wolff–Kishner reductions.

Learn how to prepare carboxylic acids from primary alcohols and Grignard reagents with carbon dioxide, via oxidation with strong oxidants in alkaline or acidic media, including benzene to benzoic acid.

Examine why carboxylic acids have higher boiling points than similar ketones and alcohols, due to strong hydrogen bonding and intermolecular forces. As carbon chain length grows, water solubility decreases.

Explore how the acidity of carboxylic acids hinges on conjugate base stability, enhanced by resonance and inductive effects, and shaped by electron withdrawing or donating substituents and their positions.