Palladium-catalyzed reductive homocoupling of N′-tosyl arylhydrazines

Abstract

A novel procedure for the preparation of biaryl compounds by Pd-catalyzed homocoupling of N'-tosyl arylhydrazine has been described. N'-Tosyl arylhydrazine, as a readily available and stable coupling partner, demonstrated its generality in the homocoupling reactions. The scope of the reaction and possible mechanism have also been investigated.

Transition-Metal-Free C-3 Arylation of Quinoline-4-ones with Arylhydrazines

“…To support the radical mechanism, we carried out the radical trapping experiment by using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) under optimized conditions (Scheme ), this afforded TEMPO adduct 1-(2,2,6,6-tetramethylpiperidinyloxy)-benzene ( 6 ). On the basis of our experimental results and previous literature, ,,− we outlined a radical-mediated reaction mechanism as shown in Scheme . After formation of the free phenylhydrazine from its hydrochloride salt ( 1 ) in the presence of base, it undergoes single electron transfer in the presence of oxygen to form phenylhydrazine cation radical intermediate, which upon simultaneous loss of H + in the presence of base leads to phenylhydrazyl radical [ A ].…”

Denitrogenative Pd/Cu‐catalyzed Suzuki‐type Cross‐coupling of Aryltrifluoroborates with Arylhydrazine Hydrochlorides in Water under Room Temperature

“…In cross‐coupling arylation. Recent advances in the coupling reactions of arylhydrazine, which is utilized as an effective arylation partner in oxidative radical arylation and Pd‐catalyzed cross‐coupling (Heck‐type, Suzuki‐type, addition, homocoupling, etc …”

Copper(ii)-catalyzed coupling reaction: an efficient and regioselective approach to N′,N′-diaryl acylhydrazines

“…31 Our previous study revealed that N′-tosyl arylhydrazine was another efficient coupling partner. 32,33 In an attempt to explore a more stable coupling reagent, we noticed that N′-aryl hydrazides can be cleaved under mild oxidative conditions to afford aromatic alkenes, 34 which implied that N′-aryl hydrazides might also act as aryl donors for some coupling reactions. Herein, we reported the first copper(II)-catalyzed homo-coupling reaction of N′-aryl acylhydrazines for the synthesis of symmetrical N′,N′diaryl acylhydrazines.…”