Reductive Homocoupling Of Aryl Halides Research Articles

ChemInform Abstract: Facile Palladium‐Catalyzed Homocoupling of Aryl Halides Using 1,4‐Butanediol as Solvent, Reductant and O,O‐Ligand.

A mild, efficient and environmentally friendly method for the synthesis of biaryl compounds via palladium-catalyzed reductive homocoupling of aryl halides in 1,4-butanediol (1,4-DBO) has been developed. In this catalyst system, green solvent-1,4-butanediol is used not only as solvent, but also as reductant and O,O-ligand, and therefore no extra reducing agents and ligands are required. Moreover, the weak coordinate effect brings 1,4-butanediol close to the palladium and accelerates the process of electron transfer in a four-membered ring transition state and hence promotes the reduction and catalytic process. A variety of biaryl compounds have been synthesized via this protocol rapidly with low loading of palladium catalyst under mild conditions in air.

Facile palladium–catalyzed homocoupling of aryl halides using 1,4‐butanediol as solvent, reductant and O,O‐ligand

AbstractA mild, efficient and environmentally friendly method for the synthesis of biaryl compounds via palladium‐catalyzed reductive homocoupling of aryl halides in 1,4‐butanediol (1,4‐DBO) has been developed. In this catalyst system, green solvent‐1,4‐butanediol is used not only as solvent, but also as reductant and O,O‐ligand, and therefore no extra reducing agents and ligands are required. Moreover, the weak coordinate effect brings 1,4‐butanediol close to the palladium and accelerates the process of electron transfer in a four‐membered ring transition state and hence promotes the reduction and catalytic process. A variety of biaryl compounds have been synthesized via this protocol rapidly with low loading of palladium catalyst under mild conditions in air.

ChemInform Abstract: Polymerized Functional Ionic Liquid Supported Pd Nanoparticle Catalyst for Reductive Homocoupling of Aryl Halides.

AbstractAryl iodides and bromides react selectively to the reductive homocoupling products.

ChemInform Abstract: The Role of Magnetic Nanoparticles (MNP) as Reducing Agents in an MNP‐Supported Pd—Catalyst for the Reductive Homocoupling of Aryl Halides.

AbstractThe catalyst exhibits good activity in the synthesis of compounds (II).

The role of magnetic nanoparticles (MNP) as reducing agents in an MNP-supported Pd–catalyst for the reductive homocoupling of aryl halides

A palladium pincer catalyst grafted onto the surface of magnetic nanoparticles (MNPs) has been developed. This material effectively catalyzes the reductive homocoupling of various aryl halide substrates, with the MNP support acting as the reducing agent. The catalyst can be recycled up to five times in the absence of additional reducing agent to give almost quantitative yields of biaryl homocoupling products. After the reducing power of the MNP has been depleted, the supported Pd complex remains an effective catalyst for Suzuki–Miyaura cross-coupling.

Palladium catalyzed reductive homocoupling reactions of aromatic halides in dimethyl sulfoxide (DMSO) solution

Biaryls were obtained in good to excellent yields from the palladium catalyzed reductive homocoupling reactions of various aryl iodides and bromides in dimethyl sulfoxide (DMSO) solution without the need for any additional reducing reagents. Pd(dppf)Cl 2 is the most effective among the screened palladium catalysts for the homocoupling reactions. Fluorides, carbonates, acetates and hydroxides can be used as bases at promoting the palladium catalyzed reductive homocoupling of aryl halides in DMSO solution. X-ray photoelectron spectroscopic (XPS) analysis shows that the oxidative Pd 2+(dppf) species can be reduced into the Pd 0(dppf) active species by solvent DMSO molecules to furnish the catalytic cycle, indicating that DMSO plays a dual role as both solvent and reducing reagent. A plausible reaction mechanism has been discussed. Elimination of additional reducing reagents will not only reduce the reaction operation cost, but will also simplify the product separation and purification.

Novel and Efficient Synthesis of Symmetrical Functionalized Biaryls Using Zinc and Triethylammonium Formate.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Facile Synthesis of Symmetrical Functionalized Biaryls from Aryl Halides Catalyzed by Commercial Zinc Dust Using Ammonium Formate.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Facile synthesis of symmetrical functionalized biaryls from aryl halides catalyzed by commercial zinc dust using ammonium formate

Reductive homocoupling of aryl halides in the presence of commercial zinc dust and ammonium formate in methanol produces biaryls in good to excellent yields. Aryl halides having either electron-donating or electron-withdrawing groups underwent smooth coupling to afford the corresponding symmetrical biaryls. Addition of 1 equiv of sodium hydroxide enhanced the coupling reaction rate. Commercial zinc dust is inexpensive, widely available and can be used without any auxiliary catalysts such as Pd(0) and/or Ni(0).

Novel and Efficient Synthesis of Symmetrical Functionalized Biaryls Using Zinc and Triethylammonium Formate

Reductive homocoupling of aryl halides in the presence of commercial zinc dust and triethylammonium formate in methanol produces biaryls in good to excellent yields. Aryl halides having either electron-donating or electron-withdrawing groups underwent smooth coupling to afford the corresponding symmetrical biaryls. The reductive coupling did not occur without triethylammonium formate. Addition of one equivalent of sodium hydroxide enhanced the coupling reaction rate. The commercial zinc dust is inexpensive, widely available and can be used without any auxiliary catalysts such as Pd(0) and/or Ni(0).

ChemInform Abstract: Tetrakis(dimethylamino)ethylene (TDAE)—Pd Promoted Reductive Homocoupling of Aryl Halides.

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Tetrakis(dimethylamino)ethylene (TDAE)-Pd Promoted Reductive Homo-coupling of Aryl Halides

A combination of tetrakis(dimethylamino)ethylene (TDAE) and palladium catalysts promoted reductive homo-coupling of aryl halides efficiently to afford the corresponding biaryls in good to quantitative yields. TDAE acted as a very mild reductant, and easily reducible functional groups, such as a nitro, formyl, ester, or nitrile group, remained unchanged.

Water as Solvent for Nickel-2,2′-Bipyridine-Catalysed Electrosynthesis of Biaryls from Haloaryls

Reductive homocoupling of aryl halides into biaryls was achieved by electrolysis of aqueous emulsions, either in an undivided cell fitted with a sacrificial anode, or in a divided diaphragm cell, and in the presence of nickel-2,2′-bipyridine as catalyst. Reactions were also run in a filter-press cell.

Water as Solvent for Nickel-2,2′-Bipyridine-Catalysed Electrosynthesis of Biaryls from Haloaryls

Reductive homocoupling of aryl halides into biaryls was achieved by electrolysis of aqueous emulsions, either in an undivided cell fitted with a sacrificial anode, or in a divided diaphragm cell, and in the presence of nickel-2,2′-bipyridine as catalyst. Reactions were also run in a filter-press cell.