Chapter 3 - Reactions of Nucleophiles and Bases

Abstract

The reactions of nucleophiles and bases are usually organized on the basis of the reacting group and the overall reaction—nucleophilic addition to carbonyl groups, which gives rise to a very large number of categories. The classification is based on the structural relationship between the starting materials and products. Mechanistically, all of the reactions that are considered involve nucleophilic substitution as the first step, except for aromatic substitution via the aryne mechanism, which involves elimination followed by nucleophilic addition. There are two mechanisms for nucleophilic aromatic substitution, and both occur in two important steps. In one mechanism, an addition is followed by an elimination. In the other mechanism, an elimination is followed by an addition. This chapter provides several examples of aliphatic nucleophilic substitution at both sp3 and sp2 centers, aromatic nucleophilic substitution, E2 elimination, nucleophilic addition to carbonyl compounds, 1,4-addition to α,β-unsaturated carbonyl compounds, and rearrangements promoted by base.