Question

Draw the curved arrow mechanism for the addition of HCN in water with NaOH to heptan-4-one to give the corresponding cyanohydrin in the fewest steps. Draw the arrows that lead to the resonance structures with full octets around each atom other than hydrogen. Draw all electrons and charges if necessary on all structures; do not show any inorganic side products or counterions. Reagents needed for each step are provided in the boxes.

Answer 1

Cyanohydrin is formed through nucleophilic addition of cyanide ion to carbonyl center of the given ketone

Step-by-step explanation:

• NaOH maintains basic medium. Hence dissociation of HCN gets favored to produce nucleophile
  `CN^(-)`
• In first step,
  `CN^(-)` is produced through dissociation of HCN.
• In second step,
  `CN^(-)` gives nucleophilic addition at the cabonyl center of heptan-4-one,
• In the third step, protonation of negatively charged oxygen atom occurs leading to formation of cyanohydrin.
• Full reaction mechanism has been shown below.