Developments in Transition-Metal-Catalyzed Reactions Using Electrophilic Nitrogen Sources

Abstract

The importance of forming C-N bonds has spurred the development of reactions using electrophilic nitrogen reagents. Recently transition-metal catalysts have been developed for use with electrophilic nitrogen sources, resulting in a number of useful C-N bond-forming reactions. This review article summarizes recent progress in this field.

N-Amino pyridinium salts in organic synthesis

“…Electrophilic and radical nitrogen intermediates provide the opportunity to effect amination of nucleophilic substrates, including olefins, organometallic reagents, and C-H bonds (Scheme 1b). [12][13][14] An array of electrophilic reagents have been developed, with hydroxylamine derivatives, organoazides, and iminoiodinane reagents all featuring prominently in developed electrophilic amination methods. While each of these reagent classes has numerous attractive attributes, each face significant draw backs: as examples, access to hydroxylamine derivatives often requires pre-functionalized starting materials and multiple synthetic steps; 15,16 and, access to iminoiodinane typically requires N-sulfonyl derivatives, 17 which can enable C-H amination, but require harsh deprotection conditions that can limit product diversification.…”

Directing-Group-Free Arene C(sp2)–H Amination Using Bulky Aminium Radicals and DFT Analysis of Regioselectivity

“…Well-developed and general strategies include the reduction of nitroarenes, transition-metal-catalyzed cross-coupling reactions (i.e., Buchwald–Hartwig, Chan–Lam–Evans, etc. ), and electrophilic amination of arylmetals and arylboronic acids . More recently, C–H amination has received widespread attention as a powerful tool to access aryl amines without pre-functionalization of the aromatic substrates .…”

Cross-Coupling of Heteroatomic Electrophiles

“…One feature common to the mechanisms of all the aforementioned metal-mediated C–N bond forming reactions is that the nitrogen coupling partner acts as the nucleophile. In general, reactions in which nitrogen acts as a nucleophile are very common; reactions involving electrophilic amination are less common and have been a topic of recent interest. − Reactions combining both metals and electrophilic nitrogen in cross-coupling , will be detailed in the following sections.…”

“…In general, reactions in which nitrogen acts as a nucleophile are very common; reactions involving electrophilic amination are less common and have been a topic of recent interest. 228−233 Reactions combining both metals and electrophilic nitrogen in cross-coupling 234,235 will be detailed in the following sections. 236 and in 1999 he found that a stoichiometric reaction of palladium(0) with O-sulfonyloxime 82, followed by aqueous quench, resulted in the formation of imine 84 (Figure 23).…”