Crossed Aldol Reactions with Benzaldehyde

Benzaldehyde can take part in a crossed aldol reaction with a ketone in basic solution. Because benzaldehyde has no alpha hydrogen, it cannot enolize to form an enolate. That feature helps the reaction give one main crossed product.

This reaction is called Claisen-Schmidt condensation. In basic c...

Recall that the self-condensation of ketones in basic conditions is not favored.

Accordingly, in an aqueous base and external heating, the ketone reacts with benzaldehyde that lacks an α hydrogen to form a single unsaturated carbonyl product. This reaction is called Claisen–Schmidt condensation.

As for the mechanism, the ketone eno...