Palladium‐Catalyzed Direct Arylation of (Hetero)Arenes with Aryl Boronic Acids

Abstract

No compass required: A method is described for forming biaryl CC bonds by a PdII‐catalyzed cross‐coupling of aryl CH bonds with aryl boronic acids under mild conditions without the presence of directing groups. Different substituents on both (hetero)arenes and aryl boronic acids are compatible with the reaction conditions, and the homocoupling of boronic acids is highly inhibited. Dioxygen was applied as the final oxidant.

Synthesis of binuclear iridium(III) and rhodium(III) complexes bearing methylnaphthalene-linked N-heterocyclic carbenes, and application to intramolecular hydroamination

“…The solvent was removed to give corresponding indole compound 6 as white solid. The structures of 6a [22], 6b [23], 6c [21], 6d [24], 6e [25], 6f [22], 6g [25], 6h [22], 6i [23], 6j [19] and 6l [26] were referred to the reported data.…”

Rhodium-catalyzed regioselective arylation of phenylazoles and related compounds with arylboron reagents via C–H bond cleavage

“…Obviously, the direct arylation of arenes with arylboron reagents, in which prehalogenation of the arene coupling partners is not required, may provide a straightforward and environmentally benign method for biaryl synthesis [7][8][9][10][11][12][13][14]. As an example for the direct reaction, we have reported the multiple phenylation of benzonitrile using sodium tetraphenylborate under rhodium catalysis (Scheme 1) [15,16].…”

A Palladium/Copper Bimetallic Catalytic System: Dramatic Improvement for Suzuki–Miyaura‐Type Direct CH Arylation of Azoles with Arylboronic Acids

“…Shi et al described a Pd IIcatalyzed cross-coupling of electron-rich heteroarenes (i.e., pyrrole, furan, and thiophene derivatives) with arylboronic acids under mild conditions. [4] Studer et al reported the first direct C À H arylation of indoles with arylboronic acids and the 2,2,6,6-tetramethylpiperidine N-oxyl radical (TEMPO) as an external mild oxidant at room temperature. [5] Although the aryl-azole structural motifs are ubiquitous in biologically important natural products, synthetic pharmaceuticals, and materials, [6] it is unknown that the direct C À H arylation of azoles with arylboronic acid hitherto.…”

“…Whereas p-electron excessive five-membered heterocycles (i.e., thiophenes, furans, and pyrroles) smoothly coupled with arylboronic acids through an electrophilic mechanism, the azoles investigated herein gave only trace amount to low yields of the desired products. [4,5] Although both types of heteroarenes are electron-rich, the C2 sites of azoles are relatively electrondeficient. We believe that the distinctly differential p-electronic characteristics may induce the clear distinctness of reactivity.…”