Question

Which one of the following nucleophiles is an ambident nucleophile?

• A. \({CH}_3{O}^-\)
• B. \({HO}^-\)
• C. \({CH}_3{COO}^-\)
• D. \({H}_2{O}\)
• E. \({CN}^-\)

Hint:

Ambident nucleophiles have two different nucleophilic centers, allowing them to attack from either site. Examples include \({CN}^-\) (carbon or nitrogen) and \({NO}_2^-\) (oxygen or nitrogen).

Answer 1

Answer: (E)

Step 1: Definition of an ambident nucleophile
An ambident nucleophile is a nucleophile that can attack from two different atoms, leading to different products. 
Step 2: Analyzing the given options \({CH}_3{O}^-\) (methoxide ion): Oxygen is the only nucleophilic site, so it is not ambident. 
\({HO}^-\) (hydroxide ion): Only oxygen is nucleophilic, not ambident. 
\({CH}_3{COO}^-\) (acetate ion): Resonance delocalization reduces the ambident character. 
\({H}_2{O}\) (water): Oxygen is the only nucleophilic site, not ambident. 
\({CN}^-\) (cyanide ion): - This ion has two nucleophilic centers: - The carbon (\(C\)) can perform nucleophilic attack (\(C\)-attack). - The nitrogen (\(N\)) can also attack (\(N\)-attack). - This makes it an ambident nucleophile. 
Step 3: Conclusion Among the given options, only \({CN}^-\) is an ambident nucleophile. It can undergo nucleophilic substitution via both the carbon and nitrogen atoms.