Ir(III)-Catalyzed Mild C–H Amidation of Arenes and Alkenes: An Efficient Usage of Acyl Azides as the Nitrogen Source

Abstract

Reported herein is the development of the Ir(III)-catalyzed direct C-H amidation of arenes and alkenes using acyl azides as the nitrogen source. This procedure utilizes an in situ generated cationic half-sandwich iridium complex as a catalyst. The reaction takes place under very mild conditions, and a broad range of sp(2) C-H bonds of chelate group-containing arenes and olefins are smoothly amidated with acyl azides without the intervention of the Curtius rearrangement. Significantly, a wide range of reactants of aryl-, aliphatic-, and olefinic acyl azides were all efficiently amidated with high functional group tolerance. Using the developed approach, Z-enamides were readily accessed with a complete control of regio- and stereoselectivity. The developed direct amidation proceeds in the absence of external oxidants and releases molecular nitrogen as a single byproduct, thus offering an environmentally benign process with wide potential applications in organic synthesis and medicinal chemistry.

N-Acyloxyphthalimides as Nitrogen Radical Precursors in the Visible Light Photocatalyzed Room Temperature C–H Amination of Arenes and Heteroarenes

“…7 The vast majority of synthetically useful arene C–H amination methods involve either ligand-directed 8−11 or intramolecular 12,13 C–N bond formation. In contrast, intermolecular C–H amination of simple arenes/heteroarenes remains significantly more challenging.…”

Mechanochemical Iridium(III)‐Catalyzed C−H Bond Amidation of Benzamides with Sulfonyl Azides under Solvent‐Free Conditions in a Ball Mill

“…[2] In recent years, direct transition-metal-catalyzed CÀHf unctionalization processes of unactivated aromatic compounds were established as straightforward and elegant ways to form agreat variety of new carbon-carbon or carbon-heteroatom bonds.I nt his context, Chang and others [3][4][5][6] have reported transition-metalcatalyzed C À Nb ond formation reactions using azides as the nitrogen source where dinitrogen is formed as the sole byproduct. Fors uch transformations,I r III catalysts were particularly effective in activating aromatic compounds with weakly coordinating directing groups in the ortho position.…”

“…Fors uch transformations,I r III catalysts were particularly effective in activating aromatic compounds with weakly coordinating directing groups in the ortho position. [6] Unfortunately,h owever,m ost procedures involve the use of significant amounts of solvents,w hich reduces the overall sustainability of the processes.…”

“…[9,10] Our group reported the first catalytic mechanochemical CÀHbond functionalization process under solvent-free conditions that proceeds via an active Rh III intermediate catalyzing an oxidative Hecktype olefination process of acetanilides and olefins with dioxygen as terminal oxidant (Scheme 1a). [11] Inspired by the reports on Ir III -catalyzed C À Hb ond functionalization [6] and encouraged by our previous work, we wondered whether adequately substituted aromatic compounds would undergo mechanochemically induced Ir III -catalyzed amidation reactions in ball mills under solventfree conditions.Herein, we report the implementation of this concept (Scheme 1b).…”

Practical Pd(TFA)2-Catalyzed Aerobic [4+1] Annulation for the Synthesis of Pyrroles via “One-Pot” Cascade Reactions

“…On the other hand, the transition-metal-catalyzed sp 2 C-H amination reaction is one of the most demanding procedures to form C-N bonds [36,37]. In recent years, various late transition metal catalysts such as Pd [38][39][40][41], Ru [42], Rh [43], Ir [44], and Cu [45] have been applied in sp 2 C-H bond amination. Within this methodology, Pd-catalyzed intramolecular aza-Wacker-type oxidative reactions represent one crucial route to produce a range of 5-membered N-containing heterocycles [46][47][48][49][50][51].…”