Answering Organic Synthesis Questions

Organic synthesis questions are among the most challenging in the Edexcel Chemistry papers — and among the most rewarding. They test your ability to link reactions together into multi-step routes, applying reagents, conditions, and mechanisms to convert one molecule into another.

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What Examiners Expect

When a question asks you to outline a synthesis route, you must provide:

1. Reagents — the chemical(s) used in each step
2. Conditions — temperature, catalyst, solvent, UV light, reflux, etc.
3. The reaction type — if asked (e.g., nucleophilic substitution, electrophilic addition)
4. Intermediate products — show what is formed at each step

Simply naming the reaction type is not enough. You must specify both reagents and conditions.

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Key Functional Group Interconversions

The heart of organic synthesis is knowing how to convert one functional group into another. Here are the essential transformations:

From Alkenes

• Alkene → Alcohol: Steam (H₂O), H₃PO₄ catalyst, 300°C, 60 atm (or dilute H₂SO₄ then water)
• Alkene → Halogenoalkane: HBr (gas) at room temperature (Markovnikov addition)
• Alkene → Dihalide: Br₂ at room temperature
• Alkene → Polymer: High pressure, initiator (addition polymerisation)