A level Chemistry · Edexcel 9CH0 · Topic 18C
Organic synthesis
Key points
- Multi-step synthesis: map functional group changes, identify intermediates and give reagents and conditions for each step.
- Add a carbon with KCN (nitrile), or with HCN to a carbonyl; build carbon–carbon bonds onto benzene with Friedel–Crafts.
- Grignard reagents (RMgBr, made in dry ether) react with carbonyls and CO₂ to make longer-chain alcohols and acids.
- Practical techniques: heating under reflux, distillation, solvent extraction with a separating funnel, drying with anhydrous salts, recrystallisation and melting point determination for purity.
- Check purity: a pure solid melts sharply at its data-book value; impurities lower and widen the range.
- Consider hazards (toxic, flammable, corrosive reagents) and how to reduce risk, as well as yield and atom economy when choosing a route.
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Organic synthesis is where the whole organic course comes together: given a starting material and a target, you choose a route, the reagents and conditions for each step, and the practical methods to make and purify the product safely.
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