41. An asymmetric variant of this reaction utilizes acyl nucleophile equivalents generated by N-heterocyclic carbene catalysis. 42. Serine and cysteine proteases use different amino acid functional groups ( alcohol or thiol ) as a nucleophile . 43. In order to activate that nucleophile , they orient an acidic and basic residue in a catalytic triad. 44. The azide anion behaves as a nucleophile ; it undergoes nucleophilic substitution for both aliphatic and aromatic systems. 45. This reaction is similar to nucleophilic aliphatic substitution where the reactant is a nucleophile rather than an electrophile. 46. In electrophilic amination, the amine as the nucleophile react with another the organic compound as the electrophile. 47. This is likely in cases when the allyl compound is unhindered, and a strong nucleophile is used. 48. The iodide leaving group in methyl iodide may cause side reactions, as it is a powerful nucleophile . 49. Once a nucleophile attacks and a tetrahedral intermediate is formed, the energetically favorable resonance effect is lost. 50. The benzoate anion acts as a nucleophile again to displace iodide through a neighboring-group participation mechanism.
