Question

Explain this curious result. What does this reaction tell you about the relative reactivity of esters and ketones?

Short answer

Mechanism for reaction

Formation of the desired product

Step-by-step solution

The mechanism for the reaction

The product combination indicates that the ketone is more reactive as compared to the ester. Therefore, as soon as a small amount of ketone is formed, further attack by Grignard reagent takes place, although an excess amount of ester remains unreacted.

Mechanism for reaction

Formation of product

The low reactivity of ester can be attributed to the resonance of the oxygen lone pair with the carbonyl group, which decreases the electron deficiency of the carbonyl carbon.

Formation of the desired product