The relative reactivity of acyl compounds toward nucleophilic acyl addition-elimination is:
A)Amide ester acid anhydride acyl chloride
B)Acyl chloride ester acid anhydride amide
C)Ester acyl chloride acid anhydride amide
D)Acyl chloride acid anhydride ester amide
E)Acid anhydride acyl chloride ester amide

Question

The relative reactivity of acyl compounds toward nucleophilic acyl addition-elimination is:
A)Amide > ester > acid anhydride > acyl chloride
B)Acyl chloride > ester > acid anhydride > amide
C)Ester > acyl chloride > acid anhydride > amide
D)Acyl chloride > acid anhydride > ester > amide
E)Acid anhydride > acyl chloride > ester > amide

Quizplus · Accepted Answer

The order of reactivity towards nucleophilic acyl addition-elimination is directly proportional to the electrophilicity of the carbonyl carbon in the acyl compound. Acyl chloride has the highest electrophilicity because the chloride ion is a strong electron-withdrawing group, making the carbonyl carbon highly susceptible to attack by a nucleophile. Acid anhydride has a slightly lower electrophilicity because they have two carbonyl groups in proximity, which can decrease the positive charge on the carbonyl carbon. Ester has even lower electrophilicity because the alkyl groups can donate electron density to the carbonyl carbon, reducing its reactivity. Finally, amide has the lowest electrophilicity because the N lone pair can donate electron density to the carbonyl carbon, making it the least reactive towards nucleophilic addition. Therefore, the order of reactivity is D) Acyl chloride > acid anhydride > ester > amide.

The Relative Reactivity of Acyl Compounds Toward Nucleophilic Acyl Addition-Elimination