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Electrophilic amination is a class of organic reactions where C—N bonds are formed via the use of electrophilic aminating reagents [1–4]. Depending on the specific reaction pathway, electrophilic amination reactions can be classified either as substitution or addition. This chapter focuses on substitution reactions. Aminating reagents for the substitution‐type electrophilic aminations are essentially NR₂⁺ synthons, and the electrophilicity on the nitrogen atom is generally achieved by attaching a more electronegative functionality (X) to the nitrogen atom that can serve as a leaving group. Common structural motifs for this class of reagents include chloramines, hydroxylamines, and oxaziridines (i.e. cyclic hydroxylamine derivatives). Because of the safety hazards associated with the use of chloramines, recent developments in this area have been focused on the use of more stable hydroxylamine‐type reagents (Scheme 1.1).

Substitution‐type electrophilic amination reactions can operate under either uncatalyzed or catalyzed conditions. The majority of catalytic substitution‐type electrophilic amination reactions are catalyzed by complexes of transition metals (TMs). In the uncatalyzed reactions, the carbon nucleophile directly attacks the electrophilic nitrogen atom and a new C—N bond is formed. In the TM‐catalyzed reactions, the transition metal first enters into the N—X bond via an oxidative addition, and the new C—N bond is formed after sequential ligand exchange and reductive elimination (Scheme 1.2). The major difference between TM‐catalyzed substitution‐type electrophilic amination reactions and TM‐catalyzed C–N cross‐coupling reactions (i.e. Buchwald–Hartwig coupling) is the role of the nitrogen source: it acts as an electrophile in the former while as a nucleophile in the latter.

The majority of the literature in this area concerns the TM‐catalyzed versions of substitution‐type electrophilic amination. Therefore, they will be discussed first in this chapter.

Scheme 1.1 General structure of electrophilic aminating reagent.

Scheme 1.2 Mechanisms of two main types of electrophilic amination.