Question

Why cn- is highly specific base in benzoin condensation?

Answer 1

It acts as a nucleophile, facilitates proton abstraction, and is also the leaving group in the final step. The benzoin condensation is in effect a dimerization and not a condensation because a small molecule like water is not released in this reaction. For this reason the reaction is also called a benzoin addition.

Answer 2

Explanation:

The cyanide ion helps the reaction to occur by acting as a nucleophile and facilitating the abstraction of protons, thus forming cyanohydrin. The cyanide ions serve as a catalyst in the reaction.