Rank the following carboxylic acid derivatives in decreasing order (most to least)of reactivity towards nucleophilic substitution.

Question

Quizplus · Accepted Answer

In nucleophilic substitution reactions, carboxylic acid derivatives can undergo two mechanisms: acyl substitution (SN1-like) and nucleophilic addition-elimination (SN2-like). The reactivity of the derivatives depends on the ability of the nucleophile to attack the carbon of the carbonyl group, which is facilitated by the ability of the leaving group to leave. The leaving group ability follows the trend: carboxylic acid < ester < amide < anhydride. Therefore, the least reactive derivative towards nucleophilic substitution is the anhydride (IV), followed by the amide (III), the ester (II), and the carboxylic acid (I). Therefore, the decreasing order of reactivity towards nucleophilic substitution is I > III > II > IV. Thus, choice C is the correct answer.

Rank the Following Carboxylic Acid Derivatives in Decreasing Order (Most