What is the product of the aldol condensation between 4-methylbenzaldehyde and 4-methylcyclohexanone?

1 Answer
Apr 27, 2018

Here's what I get.

Explanation:

The aldol condensation involves attack of an enolate ion on a carbonyl compound to form a β-hydroxycarbonyl adduct (an aldol).

Aldol condensationAldol condensation
(from www.chem.ucla.edu)

The aldol can then dehydrate to form an α,β-unsaturated carbonyl compound.

The process requires an active methylene adjacent to a carbonyl group.

If there are two active methylenes, the condensation can occur on each side of the carbonyl group.

For example, benzaldehyde with acetone gives dibenzalacetone.

1.bp.blogspot.com1.bp.blogspot.com

By analogy, I predict that the reaction of 4-methylbenzaldehyde with cyclohexanone will form
(2E,6E)-4-methyl-2,6-bis(4-methylbenzylidene)cyclohexanone.

ProductProduct

The E,E isomer should be more stable because the steric interactions of the ortho hydrogens with the "H" atoms on the cyclohexane ring are smaller than those with the carbonyl oxygen