Good evening! Very often in organic reactions, especially in reactions of rearrangements, including those involving keto groups, the course of reactions is, in principle, possible only in the presence of cyanides. Why is it so? What is the uniqueness of cyanides?
I don't quite understand what are you talking about. Can you please share some links or maybe names of the reactions?
The only thing I can say is that cyanides are a very strong nucleophiles
Aldehyde cyanohydrines is a type of something called umpolung, that means the carbon atom gets the ability to carry a "fake" negative charge in contrast to the carbon of usual aldehyde group which is sligltly positive-charged. That flips a carbonyl carbon from an electrophile to a nucleophile. I've drawn a good picture of that but can't add(