Organic Chemistry II Problem Solving

The ability to solve multi-step organic chemistry problems is the ultimate test of your understanding at A-Level. This lesson brings together everything from Organic Chemistry II — carbonyl compounds, carboxylic acids, esters, amines, amino acids, polymers, synthesis, and mechanisms — and applies it to the kinds of extended problems you will encounter in the exam.

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Multi-Step Synthesis Design

Synthesis problems at A-Level typically provide a starting material and a target molecule, and ask you to plan the route between them. The approach is always the same:

1. Compare the starting material and the target — what has changed? (functional group, chain length, or both)
2. Work backwards from the target (retrosynthesis) to identify the immediate precursor
3. Choose reagents and conditions for each step
4. Check that each step is chemically reasonable and does not introduce unwanted side reactions

Example Problem

Starting material: Propan-1-ol Target: Propanoyl chloride

Analysis: The functional group changes from alcohol (–OH) to acyl chloride (–COCl). The carbon chain length stays the same (3 carbons). The route must go through the carboxylic acid.