Arrange the following acid derivatives in the decreasing order of their intrinsic reactivity towards — Reaction Mechanism Chemistry Question
Question
Arrange the following acid derivatives in the decreasing order of their intrinsic reactivity towards nucleophilic acyl substitution ($AN+DN$ mechanism): Acid chloride (I), Ester (II), Acid anhydride (III), Amide (IV).
💡 Solution & Explanation
The reactivity of acid derivatives in the addition-elimination ($AN+DN$) mechanism heavily depends on the leaving group ability. Weaker bases are more stable and thus serve as better leaving groups. The basicity order of the leaving groups is $Cl^- < RCOO^- < RO^- < NH_2^-$. Therefore, the leaving group ability and overall reactivity order is Acid Chloride > Acid Anhydride > Ester > Amide.