Reductive Homocoupling Research Articles

Why a cathodic activation by silver interface? Facile reductive homocoupling of 1-iodoalkanes

Smooth silver electrodes were used for the cathodic one-electron cleavage of primary alkyl iodides, RI. It has been shown that the catalytic process making possible the reduction of RI species is based on pre-reacting alkyl iodides with silver. It is then proposed that the transient species formed (via electron transfer?) at the silver interface could be written as R–Ag +, I −. Arguments to support this proposal are presented. Such chemically modified interfaces showed a specific electrochemical behaviour in propylene carbonate (PC) in the presence of tetraalkylammonium ammonium salts. Experimental conditions for yielding specifically a one-electron step for RI species are discussed and the resulting homocoupling is evidenced.

ChemInform Abstract: Facile Synthesis of Bibenzyl by Reductive Homocoupling of Benzyl Halides in Aqueous Media.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A Stereoselective Palladium‐Mediated Reductive Coupling of Electron‐Deficient Terminal Iodoalkenes

AbstractIodoacrylate esters undergo palladium‐catalysed reductive homocoupling to derive dienyl diester derivatives. This reductive coupling can be extended to ester‐substituted terminal iododienes to derive tetraene diesters. In all cases, the reactions show relatively high levels of stereocontrol, which shows an inversion of stereochemistry about one iodoalkene unit. This process, and the suggestion that the reaction releases diiodine, is consistent with a syn‐1,2‐addition of an iodopalladium(II)‐alkene species across another iodoalkene unit (carbometallation step), followed by reductive syn‐elimination of iodopalladium iodide to derive palladium(II) iodide. It appears that under the reaction conditions employed, palladium(II) iodide may equilibrate to palladium(0) and diiodine, which can be observed or trapped out from the reaction mixture.

Facile Synthesis of Bibenzyl by Reductive Homocoupling of Benzyl Halides in Aqueous Media

A facile synthesis of bibenzyl derivatives by reductive homocoupling reaction is described. Treatment of benzyl halides with metallic iron powder in the presence of a catalytic amount of cuprous salt in aqueous media gives bibenzyls in good yields.

Catalytic reductive homocoupling of 9-bromofluorene

A number of organometallic compounds and inorganic salts, including the group 8 metal carbonyls M 3(CO) 12 and salts MCl 3 (M = Fe, Ru, Os), were tested for their catalytic activity in the reductive coupling of 9-bromofluorene. Among them, FeCl 3 was found to show excellent activity (TOF = 1960). The reaction is believed to proceed via a radical mechanism.

Oxidative Generation of Diarylcarbenium Ion Pools

"Cation pools" of diarylcarbenium ions have been generated by the oxidative C-H bond dissociation of diarylmethanes using anodic oxidation. "Diarylcarbenium ion pools" thus generated react with various nucleophiles, such as allylsilanes, ketene silyl acetals, and aromatic compounds. The reductive homocoupling of the "diarylcarbenium ion pool" has been achieved. The dimer thus obtained also serves as a precursor of the "diarylcarbenium ion pool" via oxidative C-C bond dissociation. [reaction: see text]

Reaction of (η 2-arylaldehyde)nickel(0) complexes with Me 3SiX (X=OTf, Cl). Application to catalytic reductive homocoupling reaction of arylaldehyde

Arylaldehydes can coordinate to nickel(0) in η 2-fashion to give η 2-arylaldehydenickel complexes, which react with Me 3SiOTf or Me 3SiCl to give η 1:η 1-siloxybenzylnickel or η 3-siloxybenzyl complex. In the presence of PCy 3 or CO, η 1:η 1-siloxybenzylnickel complex underwent homocoupling reaction to give a pinacol type product. In the presence of zinc dust, the reductive homocoupling reaction of arylaldehyde proceeded catalytically to form pinacol derivatives in 70–99% yield. On the other hand, η 3-siloxybenzylnickel complex regenerated benzaldehyde and Me 3SiOTf under a carbon monoxide pressure.

Tandem Pd/C‐Catalyzed Reductive Coupling and Dehalogenation of Benzylic Halides

High‐yield reductive homocoupling of benzotrichloride and benzal chloride followed by consecutive reductive dechlorination to 1,2‐dichlorostilbene and stilbene is effected in the presence of sodium formate as the reducing agent and Pd/C catalysts.

Highly Diastereoselective and Enantioselective Synthesis of Enantiopure C2‐Symmetrical Vicinal Diamines by Reductive Homocoupling of Chiral N‐tert‐Butanesulfinyl Imines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Highly Diastereoselective and Enantioselective Synthesis of Enantiopure C2-Symmetrical Vicinal Diamines by Reductive Homocoupling of Chiral N-tert-Butanesulfinyl Imines

[reaction: see text] An efficient and straightforward method for the preparation of highly enantiomerically enriched C2-symmetrical vicinal diamines by the reductive homocoupling of aromatic N-tert-butanesulfinyl imines in the presence of SmI2 and HMPA was developed. It gives access to a variety of enantiopure C2-symmetrical 1,2-diamines in a very mild and practical way.

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).

A Novel Route to the Fluorinated Diimines: Carbon Monoxide‐Promoted Reductive Homocoupling of Fluorinated Imidoyl Iodides in the Presence of a Palladium Catalyst.

A new catalytic access to the fluorinated diimines which involves palladium(0)-catalyzed reductive dimerization of the imidoyl iodides is presented.

A novel route to the fluorinated diimines: carbon monoxide-promoted reductive homocoupling of fluorinated imidoyl iodides in the presence of a palladium catalyst

A new catalytic access to the fluorinated diimines which involves palladium(0)-catalyzed reductive dimerization of the imidoyl iodides is presented.

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

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Bismuth Trichloride Catalyzed Efficient Reductive Etherification of Carbonyl Compounds with Alcohols: A Novel Method for Preparation of Symmetrical and Unsymmetrical Ethers

Abstract The reductive homocoupling of a carbonyl compound and heterocoupling of a carbonyl compound with a non-protected alcohol were both effected smoothly at room temperature with triethylsilane in the presence of a catalytic amount of bismuth trichloride to afford the corresponding ethers in good yields.

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.