Final answer:
Carboxylic acid derivatives are ordered by reactivity in nucleophilic acyl substitution from most to least as acid halides, acid anhydrides, esters, and amides. Their reactivity is influenced by the ability of the group attached to the acyl carbon to leave, making halides the most reactive and amides the least.
Step-by-step explanation:
The reactivity of carboxylic acid derivatives in nucleophilic acyl substitution reactions plays a significant role in organic synthesis. The order of reactivity, from most reactive to least reactive, is as follows:
- Acid halides (R-C-Cl)
- Acid anhydrides (R-C-O-C-R)
- Esters (R-C-OR)
- Amides (R-C-NH₂)
The above order indicates that groups higher in reactivity can generally be converted into groups lower in the order, but not the reverse. For example, an acid chloride can easily be converted to an amide but converting an amide to an acid chloride under normal conditions is not feasible.
The reactivity is influenced by the leaving group ability where halogens like chlorine are the best-leaving groups, and amines are the worst-leaving groups. The positions of carboxylic acids and carboxylates were not included in this list, but they are known to be less reactive than amides when it comes to acyl substitution reactions due to their stable resonance structure and inability to leave as a good leaving group.