Ligand‐Promoted ortho‐CH Amination with Pd Catalysts

Abstract

2,4,6-Trimethoxypyridine is identified as an efficient ligand for promoting a Pd-catalyzed ortho-C-H amination of both benzamides and triflyl-protected benzylamines. This finding provides guidance for the development of ligands that can improve or enable Pd(II)-catalyzed Csp2-H activation reactions directed by weakly coordinating functional groups.

A General Method for Aminoquinoline-Directed, Copper-Catalyzed sp2 C–H Bond Amination

“…In pathway C, an arene C–H bond is functionalized by an electrophilic amination reagent, which may be either a nitrene source or an amine possessing a leaving group. 4 Although C–H bond coupling components are widely available, only a very limited number of electrophilic nitrogen sources are commercially accessible. Currently, most examples of C–H bond aminations feature reactivity by pathway C. Iridium, rhodium, and cobalt catalysts have been used in the amination of directing-group-containing arenes with azides, acetoxycarbamates, and dioxazolones.…”

“…Currently, most examples of C–H bond aminations feature reactivity by pathway C. Iridium, rhodium, and cobalt catalysts have been used in the amination of directing-group-containing arenes with azides, acetoxycarbamates, and dioxazolones. 4a–d Ellman has shown that aryl azides can be reacted with imines under rhodium catalysis to afford acridines. 4e Nakamura has used an aminoquinoline directing group to couple arenes with secondary chloroamines under iron catalysis, and Miura has disclosed copper-catalyzed reactions of heterocycles with chloroamines.…”

“…4a–d Ellman has shown that aryl azides can be reacted with imines under rhodium catalysis to afford acridines. 4e Nakamura has used an aminoquinoline directing group to couple arenes with secondary chloroamines under iron catalysis, and Miura has disclosed copper-catalyzed reactions of heterocycles with chloroamines. 4f,g Nitrosobenzenes, azodicarboxylates, and hydroxysuccinimide derivatives have been used as electrophilic nitrogen sources.…”

“…4e Nakamura has used an aminoquinoline directing group to couple arenes with secondary chloroamines under iron catalysis, and Miura has disclosed copper-catalyzed reactions of heterocycles with chloroamines. 4f,g Nitrosobenzenes, azodicarboxylates, and hydroxysuccinimide derivatives have been used as electrophilic nitrogen sources. 4h–k Ackermann has reported that azides can be coupled with arenes under ruthenium catalysis.…”

“…4f,g Nitrosobenzenes, azodicarboxylates, and hydroxysuccinimide derivatives have been used as electrophilic nitrogen sources. 4h–k Ackermann has reported that azides can be coupled with arenes under ruthenium catalysis. 4l Hydroxyl-amine derivatives have been used as sp 2 C–H bond aminating reagents by a number of groups.…”