21. This is different from an electrophilic aromatic substitution reaction in which nitronium ions are the electrophile. 22. Both steps are reversible and as a result, nucleophilic acyl substitution reactions are equilibrium processes. 23. Chiral transmission is assumed to take place through so-called substitution reactions of serine clusters. 24. "' Iododesilylation "'is a substitution reaction of silyl group for iodide. 25. The Chan rearrangement is another example of a rearrangement resulting from an intramolecular nucleophilic acyl substitution reaction . 26. The second substitution reaction ( on the right ) is slower because the first nitro group is deactivating. 27. During his study of alkyl halides, Ingold found evidence for two possible reaction mechanisms for nucleophilic substitution reactions . 28. In this polar basic substitution reaction mechanism, thiocyanate ion extracts the acidic proton from benzoic acid while heated. 29. How could one tell whether a substitution reaction is proceeding via an associative rather than a dissociative reaction pathway? 30. In this context a substitution reaction was one such as { alcohol } + acid { ester } + water.
