Answer:
4-oxopentanoic acid.
Explanation:
In this case, we must remember that the Grignard reaction is a reaction in which <u>carbanions</u> are produced. Carboanions have the ability to react with CO2 to generate a new C-C bond and a carboxylate ion. Finally, the acid medium will protonate the carboxylate to produce the <u>carboxylic acid group. </u>
The molecules that can follow the mechanism described above are the molecules: p-methylbenzoic acid, cyclopentane carboxylic acid and 3-methylbutanoic acid. (See figure 1)
In the case of <u>4-oxopentanoic acid</u>, the possible carbanion <u>will attack the carbonyl group</u> to generate a cyclic structure and an alcohol group (1-methylcyclopropan-1-ol). Therefore, this molecule cannot be produced by this reaction. (See figure 2)
