Organic Conversions, Isomerism and Reasoning

80 lessons, pages 2821–2900.

Why Organic Conversions Matter — Turning one functional group into another as the core skill of organic chemistry
The Functional Group Map — Linking alkanes, alkenes, haloalkanes, alcohols, carbonyls, acids and amines
Reading a Conversion Problem — Comparing start and target: carbon count, functional group and position
Oxidation Levels of Carbon — Classifying conversions as oxidation, reduction or neither
Reagent Families at a Glance — Oxidants, reductants, nucleophiles, electrophiles, acids and bases
Alkane to Haloalkane to Alcohol — Radical halogenation followed by substitution
Alcohols as Conversion Hubs — Why alcohols connect to almost every other functional group
Alcohol to Alkene and Back — Dehydration versus hydration as reverse conversions
Alcohol Oxidation Pathways — Primary to aldehyde or acid, secondary to ketone, tertiary resistant
Carbonyl Reduction Pathways — Aldehydes and ketones back to alcohols with hydride reagents
Carboxylic Acid Derivative Interconversions — Acid, acid chloride, ester, amide and anhydride as a reactivity ladder
Routes to Amines — Reduction of nitriles, amides and nitro compounds; substitution with ammonia
Aromatic Side-Chain Conversions — Oxidising alkylbenzenes and modifying groups attached to the ring
Aromatic Ring Conversions via Diazonium Salts — Nitro to amine to diazonium to phenol, halide or nitrile
Stepping Up: Adding One Carbon — Cyanide substitution, cyanohydrins and Grignard reaction with carbon dioxide
Adding Several Carbons with Grignard Reagents — Building larger alcohols from carbonyl compounds
Stepping Down: Removing One Carbon — Hofmann bromamide degradation and decarboxylation
Chain Shortening by Oxidative Cleavage — Ozonolysis and strong oxidation splitting carbon chains
Moving a Functional Group Along a Chain — Elimination then addition with Markovnikov or anti-Markovnikov control
Changing Markovnikov to Anti-Markovnikov Products — Choosing hydroboration or peroxide conditions to relocate a group
Alkene and Alkyne Interconversions — Partial hydrogenation, dihalide elimination and stereochemical outcomes
Retrosynthetic Thinking — Working backwards from the target with disconnections
Synthons and Synthetic Equivalents — Idealised fragments and the real reagents that deliver them
Planning Two-Step Conversions — Finding the intermediate that links start and target
Planning Three- and Four-Step Conversions — Chaining reactions and checking each step's compatibility
Order of Steps in Aromatic Synthesis — Using directing effects to place substituents correctly
Protecting Groups in Conversions — Masking alcohols, carbonyls and amines during other steps
Chemoselectivity in Multi-Step Routes — Reacting one functional group while leaving another untouched
Identifying Reagents from Transformations — Deducing the missing reagent in a conversion scheme
Deducing Structures from Reaction Sequences — Road-map problems with unknown compounds A, B and C
Distinguishing Tests in Conversion Problems — Using Tollens', iodoform, bromine water and carbonate tests to confirm products
Named Reactions in Conversion Chains — Placing aldol, Cannizzaro, Hofmann and Sandmeyer steps within routes
Yield Across Multiple Steps — Overall yield as a product of step yields and why short routes win
Linear versus Convergent Synthesis — Comparing route designs by efficiency
Evaluating Competing Routes — Judging routes by steps, selectivity, safety and atom economy
Isomerism Overview — Structural isomers versus stereoisomers as a classification tree
Chain and Position Isomerism — Branching and group position with the same molecular formula
Functional Group Isomerism — Alcohols and ethers, aldehydes and ketones, acids and esters
Metamerism and Tautomerism — Different alkyl groups around a functional group; keto–enol equilibria
Counting Structural Isomers Systematically — Methodical enumeration of isomers of C₄ to C₆ formulae
Degree of Unsaturation — Using the formula to count rings and pi bonds before drawing isomers
Geometrical Isomerism in Alkenes — Restricted rotation and the conditions for cis–trans isomers
E/Z Nomenclature — Applying Cahn–Ingold–Prelog priorities to double bonds
Geometrical Isomerism in Rings — Cis and trans substituents on cycloalkanes
Counting Geometrical Isomers in Polyenes — The 2ⁿ rule and reduction for symmetrical dienes and trienes
Chirality and Stereocentres — Non-superimposable mirror images and identifying chiral carbons
Assigning R and S Configuration — Priority rules and orienting the lowest priority group away
Enantiomers and Optical Activity — Rotation of plane-polarised light and specific rotation
Diastereomers — Stereoisomers that are not mirror images and their different properties
Meso Compounds — Internal symmetry making molecules with stereocentres achiral
Fischer Projections — Drawing and interpreting stereocentres in two dimensions
Converting Between Stereochemical Drawings — Wedge-dash, Fischer and Newman representations of the same molecule
The 2ⁿ Rule for Stereoisomers — Maximum stereoisomer count from n stereogenic units
Counting Stereoisomers with Symmetry — Reducing the 2ⁿ count when meso forms appear
Counting Stereoisomers: Tartaric Acid and Similar Cases — Worked counting for symmetrical molecules with two stereocentres
Counting Stereoisomers in Molecules with Double Bonds and Stereocentres — Combining E/Z and R/S stereogenic units
Counting Stereoisomers in Cyclic Compounds — Disubstituted cyclohexanes and cyclopentanes
Counting Total Isomers Including Stereoisomers — Structural plus stereo enumeration for a molecular formula
Pseudoasymmetric Centres — Centres made stereogenic by two enantiomorphic groups
Axial Chirality in Allenes and Biphenyls — Chirality without a stereocentre
Conformational Isomerism — Rotation about single bonds; staggered and eclipsed ethane and butane
Cyclohexane Conformations and Stereochemistry — Chair forms, axial and equatorial substituents and ring flips
Racemic Mixtures and Resolution — Separating enantiomers through diastereomeric salts
Enantiomeric Excess — Quantifying optical purity from observed rotation
Stereochemistry of Substitution in Conversions — Inversion in SN2 and racemisation in SN1 across a route
Stereochemistry of Addition in Conversions — Syn and anti additions creating new stereocentres
Stereochemistry of Elimination in Conversions — Anti-periplanar E2 setting alkene geometry
Stereospecific versus Stereoselective Reactions — Distinguishing guaranteed outcomes from preferred outcomes
Creating Stereocentres from Achiral Starting Materials — Why achiral reagents give racemic products
Stereoisomers Formed in Multi-Step Routes — Tracking and counting stereoisomeric products through a sequence
Chirality in Medicines and Biology — Why enantiomers can act differently in living systems
Reasoning Tools: Electron Flow Logic — Predicting products from nucleophile and electrophile sites
Reasoning Tools: Comparing Acidity and Basicity — Structure-based ranking using induction, resonance and hybridisation
Reasoning Tools: Comparing Reactivity — Ranking substrates for substitution, addition and acyl substitution
Reasoning Tools: Predicting Major Products — Weighing regiochemistry, stereochemistry and competing pathways
Assertion–Reason Problems in Organic Chemistry — Evaluating paired statements and their causal link
Common Traps in Conversion Problems — Rearrangements, over-oxidation, wrong carbon count and incompatible reagents
Integrated Conversion and Isomerism Problems — Routes that generate isomers to be identified and counted
Exam Strategy for Organic Reasoning — Structured approach to conversion, isomer and mechanism questions
Organic Conversions, Isomerism and Reasoning: Unit Review — Consolidating conversions, stereoisomer counting and reasoning skills