Rhodium‐Catalyzed Direct CH Amination of Benzamides with Aryl Azides: A Synthetic Route to Diarylamines

Abstract

No muss, no fuss: A rhodium-catalyzed direct intermolecular C-H amination of benzamides and ketoximes using aryl azides as the amine source has been developed. The reaction exhibits a broad substrate scope with excellent functional-group tolerance, requires no external oxidants, releases N(2) as the only by-product, and produces diarylamines in high yields.

Facile Synthesis of Unsymmetrical Acridines and Phenazines by a Rh(III)-Catalyzed Amination/Cyclization/Aromatization Cascade

“…Imines or azobenzenes 9 undergo ortho-directed C-H bond activation to give metallacycles 10 19 followed by coordination and migratory insertion with azides to afford metallacycle 12 . This sequence of reactions corresponds to mechanisms previously proposed for other Rh(III)-catalyzed reactions with organic azides 11a–c and is also consistent with the lack of reactivity of the aromatic azide with the Rh(III)-catalyst unless the azobenzene or imine substrate is present. Protonation of metallacycle 12 then releases diarylamine 13 and the Rh(III) catalyst.…”

“…Capitalizing on recent reports of Rh(III)-catalyzed C-H functionalization with aromatic and sulfonyl azide coupling partners, 11a–c,12,13 Glorius has very recently described a novel Rh/Cu-cocatalyzed synthesis of 1H -indazoles through C-H amidation of benzimidates with sulfonyl azides followed by oxidative N-N bond formation. 11d Herein, we report new formal [3 + 3] annulations to prepare acridines and phenazines by Rh(III)-catalyzed C-H amination with aromatic azides followed by in situ intramolecular electrophilic aromatic substitution and aromatization (Figure 1). Despite the prevalence of acridines and phenazines in natural products, pharmaceuticals and materials, 14,15 as exemplified by photosensitizers or photocatalysts, the regioselective preparation of derivatives with substitution on both rings can be 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.…”

2.9 C—N Bond Formation by C—H Functionalization via Metal-Catalyzed Nitrene Insertion

“…Scheme 23 Amination of Arenes with Aryl Azides[40] Scheme 25 Amination of Arenes with an Acyl Azide[42] …”