Question

The relative rate of nucleophilic acyl substitution for a given acid derivative (RCOX) depends on :

• A. only the resonance effect of X.
• B. both the resonance effect of X.
• C. only the inductive effect of X.
• D. neither the resonance effect nor the inductive effect.

Answer 1

The correct option is B both the resonance effect of X.

A nucleophile is an electron-rich species that will react with an electron-poor species (Nu in the scheme). An acyl group is R-C=O (where R can be alkyl or aryl),acyl group in both the starting material and the product. A substitution notes that the leaving group (LG) is replaced by the nucleophile (Nu).

There are two fundamental events in a nucleophilic acyl substitution reaction:

Formation of the news bond to the nucleophile, Nu.

Breaking of the s bond to the leaving group, LG.

In acid derivative R- COX, greater - I effect and smaller +R effect of 'X' increases reactivity in the nucleophilic substitution reaction