Question 1

How do I know which reaction to use when planning a synthesis?

Accepted Answer

It comes down to practice and pattern recognition. A great strategy is to create your own reaction map or flowchart connecting all the functional groups. For each arrow between groups, write down the exact reagents and conditions. Using this visual aid during revision will build your fluency.

Question 2

What's the difference between reflux and distillation in synthesis?

Accepted Answer

Reflux involves heating a reaction mixture with a condenser placed vertically above the flask. This allows the reaction to be heated for a long period without losing volatile substances, as they condense and drip back down. It's used to ensure a reaction goes to completion. Distillation is a separation technique. It's used either to purify a final liquid product or, crucially in synthesis, to remove a product as it forms if it's more volatile than the reactants (e.g., making an aldehyde from a primary alcohol).

Question 3

Do I need to memorise all the specific conditions for every reaction?

Accepted Answer

Yes, for the most part. Reagents and conditions are intrinsically linked and are often worth separate marks in an exam. For example, stating 'acidified potassium dichromate(VI)' and 'heat under reflux' are two distinct pieces of information required to describe the full oxidation of a primary alcohol. Simply writing the reagent is not enough.

Organic synthesis

What you need to know

Building Molecules: Your Organic Roadmap