Organic chemistry is difficult to study as a list of reactions. The same reaction may depend on structure, electron movement, stereochemistry, solvent, temperature and work-up. If you memorise only the product, you may recognise a familiar example but struggle when the substrate or conditions change.
A better method is to organise the subject around patterns:
- identify the functional group and its electronic behaviour;
- predict which bond is likely to break or form;
- draw the mechanism with curved arrows;
- check regioselectivity and stereochemistry;
- use spectroscopy and analytical data to test the structure;
- practise choosing a short synthesis rather than recalling an isolated reaction.
There is no single international organic chemistry examination. Your course may emphasise reaction mechanisms, laboratory interpretation, spectroscopy, synthesis or problem-solving to different degrees. Start by checking your institution's syllabus, learning outcomes and past-paper guidance. Then build your revision around the knowledge and question types you are actually assessed on.
Organise the subject before memorising reactions
Begin with a reaction map rather than a linear set of notes. Put each reaction under the transformation it performs:
- alkene to alcohol, haloalkane or epoxide;
- alcohol to aldehyde, ketone or carboxylic acid;
- carbonyl compound to alcohol, imine or alkene;
- carboxylic acid derivative to another derivative;
- aromatic substitution;
- carbon–carbon bond formation;
- oxidation, reduction and protecting-group changes.
For every reaction, record five things:
- the starting functional group;
- the reagent and important conditions;
- the product and any major by-products;
- the mechanism or key intermediate;
- the limitation that would make the reaction unsuitable.
For example, sodium borohydride reduces aldehydes and ketones to alcohols under commonly taught conditions, but it is generally less reactive than lithium aluminium hydride and does not serve as a universal reducing agent for every carboxylic acid derivative. The distinction matters more than memorising that both are labelled “reducing agents”.
Use a separate page for conventions. Include formal charge, common oxidation states, pKa trends, nucleophile and electrophile definitions, curved-arrow rules, and the difference between constitutional, configurational and conformational isomers. These are the tools used repeatedly across the course.
Build from electron movement
For each mechanism, ask:
- Where is the electron-rich site?
- Where is the electron-poor site?
- What bond is formed by the nucleophile?
- What bond is broken, and where do those electrons go?
- Is the leaving group able to leave under these conditions?
- Does the intermediate gain or lose stability through resonance, induction or hyperconjugation?
Draw the full mechanism instead of writing “SN2” or “E1”. A correct label does not show whether you placed the arrow correctly, used the right substrate, or accounted for inversion and elimination.
Keep structure and reactivity together
Do not study alkene chemistry, alcohol chemistry and carbonyl chemistry as unrelated chapters. Connect them through electronic structure. A carbonyl carbon is electrophilic because the C=O bond is polarised. A carbonyl oxygen can be protonated, which changes the reactivity of the carbonyl group. An enolate is nucleophilic at carbon and can form a carbon–carbon bond.
The same comparison habit works for substitution and elimination. A primary haloalkane often favours SN2 with a strong nucleophile, while a tertiary substrate is more likely to undergo SN1 or E1 under conditions that stabilise a carbocation. These are trends, not automatic answers: solvent, base strength, temperature and substrate structure still need to be checked.
Put your notes into a working board
A useful revision board should contain decisions, not just copied paragraphs. Separate the board into sections that match how you solve problems: foundations, mechanisms, functional-group transformations, stereochemistry, spectroscopy and synthesis.
MySummaries can turn your own lecture notes and practical material into a board with sections, due cards and short source-linked summaries. A board on this topic ends up looking like this:
- Nucleophile — electron-pair donor; examples include I−, CN− and NH3
- Leaving group — a species that can depart with the bonding electron pair; I− is generally better than F− in protic substitution
- Curved arrows start at an electron pair or bond and point to an electron-poor atom or bond
An SN2 reaction gives inversion at the carbon undergoing substitution. E/Z assignment uses CIP priority; the higher-priority groups on the same side give Z.
| Pattern | Typical outcome |
|---|---|
| Primary haloalkane + strong nucleophile | SN2; inversion at the reacting stereocentre |
| Tertiary haloalkane in polar protic solvent | SN1/E1 competition |
| Strong base + heat | Elimination is increasingly favoured |
- IR C=O absorption is commonly near 1700 cm−1, with the exact value affected by conjugation and functional group
- 1H NMR integration gives relative proton counts; splitting follows coupling to non-equivalent neighbouring protons
- 13C NMR separates chemically distinct carbon environments
- Aldehyde and ketone carbonyl carbons are electrophilic
- NaBH4 reduces aldehydes and ketones to primary and secondary alcohols
- Grignard reagents add to carbonyl compounds; use anhydrous conditions before acidic work-up
This illustrative board is useful because it links a fact to the decision it supports. The “primary haloalkane” row tells you what to consider, while the mechanism section tells you what to draw. Keep exceptions beside the rule: tertiary substrates do not automatically give one product, and a strong base can change the outcome.
Create a small core before making a large deck
Your core list should contain facts that control many questions. It is not a catalogue of every reagent in your notes. Include rules such as relative acidity, nucleophilicity, stereochemical consequences, common oxidation patterns and spectral signals that you repeatedly use.
A good core item has a boundary. “Know carbonyl chemistry” is too broad. “NaBH4 reduces aldehydes and ketones, whereas LiAlH4 is a stronger hydride reagent that can reduce carboxylic acid derivatives” gives you a comparison to retrieve.
MySummaries can extract this short checklist from the board before you add more detailed cards. The core for this topic could look like this:
This illustrative core is short enough to revisit daily. When you miss a question, add the missing distinction rather than copying the whole explanation. For instance, if you confuse PCC with dichromate, add the oxidation endpoint and the conditions that explain it.
Study mechanisms with retrieval practice
Use flashcards for one decision or relationship at a time. Avoid cards that ask for an entire reaction family in one answer. A useful card might ask for the product of propene with HBr under ordinary ionic conditions, or the stereochemical result of an SN2 reaction. The answer should include the reason: Markovnikov addition through the more stable carbocation in the first case, and backside displacement with inversion in the second.
When you review a card, say or write the answer before revealing it. Grade it honestly:
- Again if you could not produce the answer;
- Hard if the answer was partly right or slow;
- Good if it was correct without major prompting;
- Easy if it was immediate and precise.
Do not grade a card as correct because the product looked familiar. You need to retrieve the reagent, conditions, mechanism where expected, and stereochemical outcome.
MySummaries can generate a reaction deck from the board so that each card tests one fact. The first card is shown below; the remaining cards form a short study session:
What is the major product when propene reacts with HBr under ordinary ionic conditions, and why?
2-bromopropane. Protonation gives the more stable secondary carbocation, then Br− attacks it; this is the usual Markovnikov orientation.
All 8 cards
This illustrative deck should be studied as a deck, not read as a list. Turn over each card, give the answer aloud, then choose a grade. For mechanism cards, draw the arrows on paper before checking the answer. For spectroscopy cards, explain what additional evidence you would need before assigning a complete structure.
Practise synthesis as a sequence of decisions
Once individual reactions are reasonably secure, work backwards from a target molecule. Mark the functional group you need to create and ask which bond could have been formed most recently. Then identify a plausible precursor and repeat the process until you reach a starting material allowed by the question.
For each proposed route, check:
- whether the reagent affects another functional group already present;
- whether the reaction requires dry, acidic, basic or inert conditions;
- whether regioselectivity or stereoselectivity is controlled;
- whether the order of steps creates a compatibility problem;
- whether purification or protection is likely to be necessary.
Keep retrosynthesis separate from forward justification. First find a plausible disconnection. Then write the route forwards with reagents, conditions and products. This prevents a familiar reagent from being inserted simply because it appears in your notes.
Use spectroscopy as evidence, not decoration
For an unknown structure, combine the data rather than interpreting each spectrum in isolation. Start with molecular formula and calculate the degree of unsaturation if the formula is available. Then use IR to identify likely functional groups, 1H NMR for proton environments, integration and coupling, and 13C NMR for carbon environments. Mass spectrometry can provide molecular mass and fragmentation evidence where it is included in your course.
Record what each datum rules in and rules out. A broad O–H signal, a carbonyl absorption and an aldehyde proton are stronger together than any one signal alone. Also distinguish absence from non-observation: a weak or overlapping signal may not be decisive.
Listen to explanations after solving
An audio explanation is most useful after you have attempted the problem. It can model the order of reasoning: identify the functional group, locate the electrophile or nucleophile, choose the mechanism, then check conditions and stereochemistry. Do not use audio as a replacement for drawing structures. Pause when a mechanism begins and predict the next arrow before continuing.
MySummaries can turn the same board into an examiner-voice lecture, allowing you to revisit a difficult section while walking or travelling. A short lecture on this topic could sound like this:
Transcript · tap any word to jump there
Start with the structure, not the reagent name. In a carbonyl compound, the carbon is electron-poor and the oxygen is electron-rich because the C=O bond is polarised. That tells you why a nucleophile attacks carbon and why protonation of oxygen can make the carbonyl more reactive.
Now compare the two common substitution pathways. In SN2, the nucleophile attacks as the leaving group leaves, so the reaction is concerted and the reacting stereocentre inverts. In SN1, the leaving group departs first to give a planar carbocation; nucleophilic attack can occur from either face, although the observed ratio need not be perfectly equal.
Before accepting an answer, check the conditions. A dry ether solvent supports a Grignard reaction, but an acidic proton destroys the reagent. In spectroscopy, use several observations together: a carbonyl IR absorption, proton integration and coupling, and the number of carbon environments should all support the same proposed structure.
This illustrative lecture is most effective when you pause at each decision and predict the next step. Re-listen only to the section you missed, then return to a card or synthesis problem that tests it.
A weekly way to keep the system working
At the start of each week, choose two reaction families, one spectroscopy set and one synthesis problem. In each study session:
- spend 10 minutes recalling the core without notes;
- spend 25–35 minutes on mechanism and reaction cards;
- spend 30–45 minutes solving unfamiliar structures or synthesis questions;
- spend 10 minutes recording mistakes as precise corrections;
- revisit cards due that day before adding new material.
At the end of the week, sort errors into categories: wrong functional group, wrong electron movement, reagent-condition confusion, stereochemistry, spectroscopy interpretation or careless drawing. The category determines the remedy. More reaction cards will not fix a repeated curved-arrow error; drawing five mechanisms will.
How MySummaries helps
MySummaries lets you build an organic chemistry board from your own notes, then use that board for a core checklist, spaced flashcards and an examiner-voice lecture. The practical method is yours: retrieve, draw, compare, correct and revisit the exact distinction that caused the mistake.