Question

If you react 1 mole of benzaldehyde and excess ketone with a base (NaOH) catalyst to form dibenzalcetone, which of the following steps would be BEST taken to minimize the formation of a mixture of products: 1. Use a carbonyl with no alpha-H 2. Use an excess of carbonyl with no alpha-H 3. Use a ketone in the presence of an aldehyde

Answer 1

This reaction is a type of aldol condensation reaction. The basic requirement for the aldol condensation reaction is that at least one reactant should have alpha hydrogens (hydrogens present on adjacent to the carbonyl group carbon).

In the above case, one reactant is fixed as benzaldehyde, so the other reactant should definitely have the alpha hydrogens. Hence the correct option is 3. 3. Use a ketone in the presence of an aldehyde.

The ketone should be used to form dibenzalacetone is acetone.