The reactivity of carbonyl compounds toward nucleophilic attack depends greatly on the nature of the substituent attached to the acyl group (–CO–). In this problem, we are given four compounds: methyl acetate (CH\(_3\)COOCH\(_3\)), acetamide (CH\(_3\)CONH\(_2\)), acetic acid (CH\(_3\)COOH), and acetyl chloride (CH\(_3\)COCl). Let us analyze them in detail:
- Methyl acetate (CH\(_3\)COOCH\(_3\)):
The ester functional group (RCOOR') is less reactive to nucleophilic attack compared to acyl chlorides. This is primarily because the ester oxygen atom donates electron density into the carbonyl group, reducing its susceptibility to nucleophilic attack.
- Acetamide (CH\(_3\)CONH\(_2\)):
Amides have an even lower reactivity than esters. The nitrogen atom of the amide can donate electron density to the carbonyl group more effectively than oxygen in esters, resulting in decreased electrophilicity of the carbonyl carbon.
- Acetic acid (CH\(_3\)COOH):
Acetic acid is a carboxylic acid where the carbonyl carbon is involved in resonance with the hydroxyl group. Thus, the carbonyl group is less reactive towards nucleophiles compared to esters and amides.
- Acetyl chloride (CH\(_3\)COCl):
Acid chlorides are the most reactive carbonyl derivatives. The chlorine atom is a weak electron donor as well as a good leaving group, enhancing the carbonyl carbon's electrophilicity. Thus, acetyl chloride is most susceptible to nucleophilic attack among the given options.
Therefore, the correct answer is CH\(_3\)COCl, as the carbonyl group in acetyl chloride is the most susceptible to nucleophilic attack due to the electron-withdrawing effect and the excellent leaving group property of chlorine.