Aldol condensation

An enolate adds to an aldehyde and the product loses water, leaving the conjugated enone.

mechanism writtenBalanced: every atom is accounted for

What it needs, and what it gives

Reaction class: Condensation
Typical conditions: Hydroxide or an alkoxide. The aldehyde with no alpha hydrogen is the one that is attacked.
Mass balance: balanced — the co-products are written out, not dropped
Mechanism: Aldol condensation, 4 steps

Conditions are what the literature ordinarily uses, recorded so you can see whether yours are in the usual range. They are not a procedure and they are not scaled to your flask.

How it is thought to happen

A base makes the enolate, the enolate attacks the other carbonyl, and the alcohol that results loses water to leave a conjugated enone.

The base makes the enolate
The enolate attacks the other carbonyl
The alkoxide takes a proton
Water leaves and the double bond forms

This is the pathway taught for the class, not a record of what was observed. On the platform it is drawn on the structures you supply, with the curly arrows on the atoms that actually move.

Read the Aldol condensation mechanism

Try it on your own structures

Enter your reactants in the Reaction Lab. If this transformation matches what you drew, it is applied and the outcome is shown next to the records that back it — with the count of documented reactions doing the same thing on substrates like yours, rather than a confidence score.

Open the Reaction Lab Browse recorded reactions

Other condensation transformations

Imine from a carbonyl and an amine

A primary amine condenses with an aldehyde or ketone, losing water and leaving the C=N.

Aldol condensation

What it needs, and what it gives

How it is thought to happen

Try it on your own structures

Other condensation transformations

Imine from a carbonyl and an amine

Where to next

All transformations

Mechanisms

Questions