Question

The correct sequence regarding the activity of the given acid derivative towards nucleophilic substitution reaction is:

• A. $R(CO{)}_{2}O>RCON{H}_2>RCOCl$
• B. $RCOCl>RCON{H}_2>(RCO{)}_{2}O$
• C. $R(CO{)}_{2}O>RCOCl>RCON{H}_2$
• D. $RCOCl>R(CO{)}_{2}O>RCON{H}_2$

Answer 1

The correct option is D $RCOCl>R(CO{)}_{2}O>RCON{H}_2$

The ease of nucleophilic substitution depends upon the nature of leaving group. When the leaving tendency of a group in a compound is high, then the compound is more reactive towards nucleophilic substitution.
The order of leaving tendency is $C{l}^{-}>RCO{O}^{-}>N{H}_2^{-}$​ and therefore the order of reactivity of acyl compound is;
Acylchloride > Acid Anhydride > Ester > Amide