Question

What ketones or aldehydes might the following enones have been prepared from by aldol reaction?

Short answer

Compound (a) can be prepared by aldol reaction of pentan-3-one. Compound (b) can be prepared by aldol reaction of 3-methylbutanal.

Step-by-step solution

Aldol reaction for compound (a)

The structure of the compound (a) is,

This compound can be prepared by the aldol reaction of pentan-3-one.

Thus, 5-ethyl-4-methylhept-4-en-3-one is the aldol reaction product which results from the reaction of two molecules of petan-3-one.

Aldol reaction of compound (b)

The structure of compound (b) is,

This compound can be prepared by the aldol reaction of 3-methylbutanal.

Thus, 2-isopropyl-5-hex-2-enal is the aldol reaction product which results from the reaction of two molecules of 3-methylbutanal.