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CEGEP • Montreal

Organic Chemistry, 202-SNU-RE

Organic Chemistry is the course where memorization alone stops working: you have to understand the mechanisms to predict the product of a reaction you have never seen. In the revised Sciences de la nature program it carries the code 202-SNU-RE and is an option course, taken after General Chemistry (202-SN1-RE). These chapters follow it from nomenclature to synthesis and the laboratory.

14 fully corrected exercise sets (208 exercises), 14 revision sheets, and a practice paper. Free, no account needed. The same course in French.

Structure, isomerism and mechanisms

  1. 1 Nomenclature and isomerism Naming an alkane and spotting the parent-chain trap, naming a ring and an aromatic compound, functional groups and their priorities, nitrogen groups and acid derivatives, the degree of unsaturation as a counting tool. Then isomerism and stereochemistry: the map of isomers and the Z/E pair, chirality with R, S and the meso compound, wedge-and-dash, Newman and Fischer drawings, optical rotation and the resolution of a racemic mixture, and the conformations of butane read on their energy curve. A Part C adds five classics: naming alkenes and alkynes, CIP priorities with duplicated atoms, Z or E when cis and trans fail, the eight alcohols of formula C5H12O and menthol. Sheet
  2. 2 Resonance and reaction mechanisms Resonance structures and the resonance hybrid, inductive and resonance effects measured on halogenated acids, resonance and acidity, the comparative stability of carbocations, radicals and carbanions, the carbocation scale. Then the mechanisms: SN2 against SN1 and how to read energy diagrams, the bromonium bridge and the stereochemistry of addition, determining a mechanism from the rate law and the optical rotation, Markovnikov electrophilic addition, and elimination with Zaitsev's rule. A Part C adds five classics: the major resonance structure, substituted benzoic acids, a three-step profile, guanidine and vitamin C. Sheet

Hydrocarbons and alkyl halides

  1. 3 Hydrocarbons Alkanes and combustion, radical halogenation and its selectivity, additions to alkenes and Markovnikov's rule, cycloalkanes and ring strain, acidity of the terminal alkyne hydrogen. Then an exam-level part: conjugated dienes with 1,4-addition and the Diels-Alder reaction, ozonolysis and oxidation as tools for structure determination, alkene polymerization and tacticity, interconversions and multistep synthesis, and a problem on petroleum refining. A Part C adds five classics: the energy balance of halogenation, the hydration of alkynes, the stereochemistry of the Diels-Alder reaction, natural rubber and the synthesis of a pheromone. Sheet
  2. 4 Alkyl halides Classes and preparation of alkyl halides, leaving-group ability, aryl and vinyl halides and the reasons for their inertness, competition between substitution and elimination, Grignard reagents and polarity inversion. Then an exam-level part: predicting a product and designing a synthesis, the Williamson synthesis and functional group transformations, the effect of the solvent on nucleophilicity, identifying an isomer with two opposite tests, and a problem on CFCs and the Montreal Protocol. A Part C adds five classics: Hughes's experiment, E2 elimination on a cyclohexane, the Grignard reagent as a base, the numerical crowding of SN2 and the synthesis of triphenylmethanol. Sheet
  3. 5 Substitution and elimination: SN1, SN2, E1, E2 The exam-preparation set on nucleophilic substitution and elimination. The four-question diagnosis before the first arrow, curved arrows that start at an electron pair, the charge balance, R or S after an SN2 or an SN1, substitution and dehydration of alcohols in acid medium, Zaitsev's rule and the Z and E descriptors. Then exam level: the mechanism of the major product and every minor product, choosing the reagent, five statements to correct, the methylation of noradrenaline in the body and two routes to cyclohexene. A final practice exercise has you complete twelve reactions, and every classic of the course has its question: leaving groups ranked by pKa, solvent, rate laws, the tosylate, the hydride shift, the intramolecular SN2. Sheet

Functional groups

  1. 6 Aromatic compounds Hückel's rule and the four conditions of aromaticity, resonance energy measured by heats of hydrogenation, the mechanism of electrophilic aromatic substitution, activating and directing effects, Friedel-Crafts alkylation and acylation and their limits. Then an exam-level part: the mechanism put to the test by the isotope effect and reversible sulfonation, side-chain reactions, the nitration-reduction-diazotization relay, building a synthesis, and a problem on polycyclic aromatic hydrocarbons. A Part C adds five classics: aromatic heterocycles, two substituents on the ring, benzyne, the four C8H10 aromatics and the synthesis of ibuprofen. Sheet
  2. 7 Alcohols, phenols and ethers Classes of alcohols and hydrogen bonding read from three boiling points, the acidity scale from alcohol to phenol explained by resonance, the four routes to an alcohol, Zaitsev dehydration with carbocation rearrangement, and the oxidation that sorts the three classes. Then an exam-level part: the three workarounds for the poor leaving group HO⁻ with the stereochemistry of the tosylate, ether cleavage by HI, the regioselectivity of epoxides that switches sides between acidic and basic media, the identification of three isomers of C₄H₁₀O, and a full problem on ethanol from fermentation to the fuel tank. A Part C adds five classics: thiols, the pinacol rearrangement, crown ethers, ethylene oxide and phenol by the cumene process. Sheet
  3. 8 Aldehydes and ketones The carbonyl group and its polarity read from three dipole moments, nucleophilic addition in both media with the numerical hydration equilibrium from methanal to propanone, acetals as protecting groups, imines and enamines with their bell-shaped optimum pH, and a sorting of reducing agents from NaBH₄ to Wolff-Kishner. Then an exam-level part: keto-enol tautomerism and the 1,3-diketone that is more acidic than an alcohol, the aldol reaction and its crossed version, the four identification tests and the Cannizzaro disproportionation, a structure determination, and a problem on sugar as a hidden carbonyl in which three optical rotations give the proportion of the two anomers. A Part C adds five classics: the Wittig reaction, 1,2 or 1,4 addition to an enone, alpha bromination, the stereoselective reduction of a cyclohexanone and the assay of carvone. Sheet
  4. 9 Carboxylic acids and their derivatives The acidity of the carboxyl group explained by resonance and quantified on the chlorinated acids, the cyclic dimer that governs boiling points, the hierarchy of acyl chloride, anhydride, ester and amide justified by the pKa of the leaving group alone, the addition-elimination mechanism, and Fischer esterification compared with saponification. Then an exam-level part: the resonance of the amide that makes the peptide bond flat and nonbasic, interconversions and their selectivity, the Claisen condensation and the malonic ester synthesis, a structure determination, and a problem on polyesters and polyamides in which the Carothers equation shows why 98.9 percent conversion is needed. A Part C adds five classics: nitriles, lactones and lactams, the kinetics of saponification, biodiesel and penicillin. Sheet
  5. 10 Amines Classes counted on NITROGEN and not on carbon, the nitrogen inversion that rules out resolving a chiral amine, and the basicity whose order reverses between the gas phase and water. Then an exam-level part: the Hofmann elimination that gives the LEAST substituted alkene and its justification on a Newman projection, the protection of aniline by acetylation before nitration, azo coupling and its pH window, the elucidation of the four isomers of C₃H₉N, and a problem on amines in living systems where the partition curve explains why the nicotine of a cigar passes through the mouth and that of a cigarette through the lungs. A Part C adds five classics: identifying an amine by titration, the Stork method, quaternary ammoniums, the extraction of caffeine and lidocaine. Sheet

Spectroscopy and biomolecules

  1. 11 Spectroscopy and structure determination The four techniques that replace wet-chemistry tests: mass spectrometry with the nitrogen rule and the isotope clusters of chlorine and bromine, infrared where the POSITION of the carbonyl betrays the acid derivative in the exact order of its reactivity, proton NMR with its four pieces of information, and carbon-13 NMR, which counts the nonequivalent carbons. Then an exam-level part: elucidating by infrared alone and measuring its limits, reading a proton spectrum, combining the four techniques on an unknown, telling pairs of isomers apart with the right technique, and checking an aspirin synthesis through its two carbonyl bands. A Part C adds five classics: UV-visible and the Beer-Lambert law, clusters with two halogens, the McLafferty rearrangement, following an oxidation, and an amide with blocked rotation. Sheet
  2. 12 Biomolecules Organic chemistry applied to living things: the Fischer projection and the count of stereoisomers, the move to Haworth and the chair conformation that explains why glucose is the most widespread sugar, the glycosidic bond and reducing sugars, the single alpha versus beta difference that separates starch from cellulose, and the lipids where one cis bend lowers the melting point by 56 °C. Then an exam-level part: the zwitterion and the isoelectric point read from a titration curve, the four levels of protein structure, sequencing a peptide from overlapping fragments, an identification exercise, and a problem on the digestion of starch. A Part C adds five classics: oxidizing and reducing a sugar, base pairing in DNA, cholesterol, aspartame and the measurement of blood glucose. Sheet

Synthesis and the laboratory

  1. 13 Synthesis and retrosynthetic analysis The question this chapter turns around: the other pages ask what product a reaction gives, this one asks which reagents give the target. The double-shafted retrosynthetic arrow, target, synthon and synthetic equivalent, the three disconnections that pay off at the CEGEP level, carbon-halogen, carbon-oxygen and carbon-carbon by Grignard reagent, then functional group interconversion as a retrosynthetic step in its own right. Then an exam-level part on the obstacle that costs the marks: the order of steps is not free. Two aromatic targets that the same reactions reach or miss depending on their order, directing effects in a grid, the deactivation that rules out Friedel-Crafts, the overall yield that is a product and not an average, chemoselectivity and protection, five faulty routes to correct, the synthesis of benzocaine and the industrial process for 2-ethylhexan-1-ol. Sheet
  2. 14 Laboratory techniques: synthesize, purify, characterize The techniques that every chapter assumes you know and none teaches: the reflux setup and the temperature locked by the solvent, the separatory funnel where density decides everything, the acid-base extraction that separates four compounds because bicarbonate is a million times more selective than sodium hydroxide, drying over magnesium sulfate and the rotary evaporator. Then an exam-level part: the retention factor and the choice of eluent, a recrystallization worked out on a solubility curve, the cold-solvent wash that costs twenty-three times less than a hot one, the mixed melting point, five statements to correct, a synthesis carried from the flask to the weighed mass, and a column run through to the mass balance. Sheet

When the chapters are done

A full paper under exam conditions, on the whole course. Do it once every chapter is behind you: it measures what you can do on a question you have never seen.

Practice exam

Practice final exam: all of 202-SNU-RE organic chemistry

A complete paper in the format of a final exam: 12 exercises in 3 hours, marked out of 100, with a detailed solution to every question. Each exercise CROSSES at least two chapters and no question announces its method, which is precisely what makes a final exam harder than the chapter sets. Part A covers structure and mechanisms, part B comparative reactivity and selectivity, part C elucidation and analysis, and part D synthesis problems, including a summary table of the eleven ways of creating a carbon-carbon bond and five statements to correct.

  • 12 questions
  • 100 points
  • 180 minutes
Sit the paper

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