- The reaction shown is the base-catalyzed elimination of hydrogen cyanide (HCN) from a cyanohydrin (specifically, acetone cyanohydrin) to form a carbonyl compound (acetone).
- Triethylamine (NEt₃) acts as a general base catalyst. It facilitates the reaction by partially abstracting the hydroxyl proton in the rate-determining step.
- The mechanism is concerted (E2), involving simultaneous deprotonation of the OH group and beta-elimination of the CN⁻ group.
- In the transition state, partial proton transfer occurs from the substrate’s OH to NEt₃, while the C–CN bond breaks and the C=O double bond forms.
- The products are acetone and HCN. The released CN⁻ is immediately protonated by the conjugate acid of the base (HNEt₃⁺) to form HCN, regenerating the neutral NEt₃ catalyst.
- This is classified as a general base catalysis because the base participates directly in the transition state with partial proton transfer, rather than acting only as a stoichiometric reagent.
Parent Tip: Review the logic above to help your child master the concept of acid base catalysis.
