Cupric Halides Research Articles

CuX2 Mediated Facile Halocyclization of N‐Allyl Thioureas

AbstractAn efficient protocol for the synthesis of thiazoline derivatives via electrophilic cyclization of N‐allyl thiourea derivatives with the low‐cost and readily available cupric halides has been developed. The notable features of this reaction are the formation of new C‐X and C‐S bonds, mild reaction conditions, short reaction time and the excellent yields. The present method was also employed for the preparation of corresponding oxazoline derivatives in very good yields.

Room temperature cupric halides mediated olefin alkoxylation of BODIPYs with methanol: mechanisms and scope.

We disclose an efficient methodology for olefin alkoxylation of fluorescent BODIPYs (boron-dipyrromethene) at the 3,5-styryl group with methanol by cupric halide (chloride or bromide) at room temperature. Mechanistic studies provide evidence for the alkoxylation reaction firstly initiated by a radical cation, that is, halide promotes the oxidizing ability of the Cu(ii) center to an extent that the single electron transfer (SET) from BODIPYs to the cupric ion and results in the production of a BODIPYs radical cation and Cu(i), then the BODIPYs radical cation subsequently reacts with methanol to afford the alkoxylated product. As the dialkoxylated product complexes with cuprous halide and further decreases its reducing ability, which is supported by DFT calculations, only strongly oxidative cupric bromide can mediate tetraalkoxylation and give rise to the tetraalkoxylated product. In addition, the expanded scope studies suggest that this method is also well suited for the alkoxylation of electron-rich conjugated olefins. The active benzyl bromide derivative may be another intermediate in the presence of cupric bromide. Therefore, the reaction is highly dependent on the anions of cupric salts; Cu(OAc)2, CuSO4 and Cu(NO3)2 containing weakly nucleophilic anions show no activity in alkoxylation.

Investigating a Bromide Supported Electrolyte for an All-Copper Flow Battery

This work investigates a bromide supported electrolyte for use in an all-copper flow battery (CuFB). In this battery, halide ions stabilize the cuprous ion. During charge, the cuprous halide complex is reduced to copper metal at the negative electrode and the complex is oxidized to a cupric halide complex at the positive electrode. Our measurements indicated that the CuFB utilizing a bromide electrolyte can achieve a higher open circuit potential (OCP) as compared to using a chloride electrolyte. The CuFB has negligible hydrogen and bromine evolution indicating that high coulombic efficiencies are achievable. A bromide supported all-CuFB with graphitic porous felt electrodes was demonstrated and the OCP after the initial charge was observed to be 0.81 V. The cell was cycled with a geometric current density of 150 mA cm−2 for 50 cycles with state of charge swings of 0 to 60%, and had a voltaic efficiency of 64%, however, copper electrodeposits were nodular and non-adherent to the substrate. We conclude that further understanding of plating morphology and the effect of substrates are necessary to take advantage of this chemistry in a conventional hybrid battery configuration, and that this system could benefit from a slurry electrode.

ChemInform Abstract: An Efficient Synthesis of Substituted Furans by Cupric Halide‐Mediated Intramolecular Halocyclization of 2‐(1‐Alkynyl)‐2‐alken‐1‐ones.

An efficient synthesis of 3-halofurans by the intramolecular cyclization of 2-(1-alkynyl)-2-alken-1-ones with cupric halide has been developed. A broad range of 3-chloro- and 3-bromofuran derivatives could be obtained in the present method in moderate to good yields. The 3-halofuran derivatives are potential synthetic intermediates for amplification of molecular complexity.

An Efficient Synthesis of Substituted Furans by Cupric Halide-Mediated Intramolecular Halocyclization of 2-(1-Alkynyl)-2-alken-1-ones

An efficient synthesis of 3-halofurans by the intramolecular cyclization of 2-(1-alkynyl)-2-alken-1-ones with cupric halide has been developed. A broad range of 3-chloro- and 3-bromofuran derivatives could be obtained in the present method in moderate to good yields. The 3-halofuran derivatives are potential synthetic intermediates for amplification of molecular complexity.

ChemInform Abstract: Highly Efficient Synthesis of Multisubstituted Furans Through Cupric Halide Mediated Intramolecular Halocyclization of 1‐(1‐Alkynyl)cyclopropyl Ketones.

A convenient and efficient method for the synthesis of 3-halofurans was developed by using a cascade reaction between 1-(1-alkynyl)cyclopropyl ketones and cupric halide. Under mild reaction conditions, both 3-chloro- and 3-bromofuran derivatives were obtained in high yields. The reaction involves consecutive multiple bond formations, includingC–O and C–Br bonds, with high regioselectivity. Mechanistic aspects are described.

Highly Efficient Synthesis of Multisubstituted Furans through Cupric Halide‐Mediated Intramolecular Halocyclization of 1‐(1‐Alkynyl)cyclopropyl Ketones

AbstractA convenient and efficient method for the synthesis of 3‐halofurans was developed by using a cascade reaction between 1‐(1‐alkynyl)cyclopropyl ketones and cupric halide. Under mild reaction conditions, both 3‐chloro‐ and 3‐bromofuran derivatives were obtained in high yields. The reaction involves consecutive multiple bond formations, includingC–O and C–Br bonds, with high regioselectivity. Mechanistic aspects are described.

Oxidative tandem alkoxide conjugate addition to nitroalkenes/radical 5- exo cyclizations—a versatile synthesis of functionalized 3-nitrotetrahydrofurans

Structurally diverse functionalized 4-(1-haloalkyl)-3-nitrotetrahydrofurans were conveniently obtained in moderate to good yield and moderate to very good diastereoselectivity by an oxidative tandem process consisting of conjugate addition reaction of lithium allyloxides to nitroalkenes followed by SET oxidation of the resulting nitronates. This triggers a radical cyclization; ligand transfer from the oxidant provides the products. The influence of the counter ion of the initial alkoxide and intermediate nitronate, the solvent and additives on the outcome of the tandem process was investigated. Optimal conditions for the tandem reactions consist of using butyllithium as the base for deprotonation in DME as the solvent. Cupric halides proved to be the SET oxidants of choice in the tandem reactions. A stereochemical model for the radical cyclization and ligand transfer steps is proposed.

ChemInform Abstract: Copper(II)/Tin(II) Reagent for Allylation, Propargylation, Alkynylation, and Benzylation of Diselenides: A Novel Bimetallic Reactivity.

Reactions of allyl, propargyl, benzyl, and alkynyl bromides with diorganodiselenides in the presence of stannous chloride and catalytic cupric halide result in the formation of corresponding unsymmetrical selenides in good to excellent yields via a novel dicopper(selenophenyl) intermediate.

Redox and spectral behaviour of copper (II)-chloro and bromo complexes in some nonaqueous solvents

The redox behaviour of 3 × 10-3 M each of CuCl2.2H2O and CuBr2.H20 have been investigated at Platinum (Pt) electrode and 1 × 10-3 M CuCl2.2H20 at glassy carbon (GCE) electrode in dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetonitrile (AN) and ethanol/0.1 M tetrabutylammonium perchlorate (TBAP) using cyclic voltammetry. For CuCl2 System, Epc1 and E0 are more positive, ∆Ep is smaller and Ipa1/Ipc1 is > at GCE than at Pt electrode, exception being ethanol where opposite trend is observed. In ethanol, two reduction steps c1/a1 due to Cu2+/ Cu+ couple while a2/c2 due to Br-/Br2 couple are observed in CuBr2system. The electron paramagnetic resonance (EPR) features of copper (II) chloro species in DMF and DMSO show splitting of the gII in frozen solution. For frozen CuBr2 system, the spectral features in DMF, DMSO and ethanol are characterized by four small peaks in the gII and one g^ signal as found for CuCl2in ethanol. However, splitting of the gII peak occurs in AN which was not observed in similar solvent for CuCl2. Key words: Redox, spectral, voltammograph, EPR, nonaqueous, cupric halide.

ChemInform Abstract: Cupric Halide Mediated Intramolecular Halocyclization of N‐Electron‐Withdrawing Group‐Substituted 2‐Alkynylanilines for the Synthesis of 3‐Haloindoles.

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.

Cupric Halide‐Mediated Intramolecular Halocyclization of N‐Electron‐Withdrawing Group‐Substituted 2‐Alkynylanilines for the Synthesis of 3‐Haloindoles

AbstractA convenient and efficient method for the synthesis of 3‐haloindoles has been developed. Both 3‐chloro‐ and 3‐bromoindole derivatives can be obtained in high yields by the reaction of N‐electron‐withdrawing group‐substituted 2‐alkynylanilines with cupric halide in dimethyl sulfoxide (DMSO) within a short period of time. Investigation of the reaction mechanism reveals that two equivalents of cupric halide are necessary.

Halocyclization of Methyl 2‐Alkynylbenzoates to Isocoumarins Using Cupric Halides

AbstractTreatment of methyl 2‐alkynylbenzoates with two to three equivalents of CuX2 (X = Cl or Br) in refluxing acetonitrile gave isocoumarins 2 in good to excellent chemical yields.

Halocyclization of 2‐Alkynylthioanisoles by Cupric Halides: Synthesis of 2‐Substituted 3‐Halobenzo[b]thiophenes.

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, please click on HTML or PDF.

Halocyclization of 2-alkynylthioanisoles by cupric halides: synthesis of 2-substituted 3-halobenzo[ b]thiophenes

Reaction of 2-alkynylthioanisoles 3 with 2 equiv of CuX 2 (X=Br or Cl) in refluxing CH 3CN for 2.5 h gave the 2-substituted 3-halobenzo[ b]thiophenes 4 in good yields.

Lewis Acid Promoted Tandem Desulfurization and Hydroxylation of γ‐Phenylthio‐Substituted Lactams: Novel Synthetic Strategy of Isoindolobenzazepine Alkaloid, Chilenine.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Lewis acid-promoted tandem desulfurization and hydroxylation of γ-phenylthio-substituted lactams: novel synthetic strategy of isoindolobenzazepine alkaloid, chilenine

Treatment of a variety of alicyclic and aromatic γ-phenylthio-substituted lactams with Lewis acids such as cuprous or cupric halides in aqueous solution at rt was found to undergo novel tandem desulfurization and hydroxylation reactions to generate γ-hydroxylated lactams without the ring-opened products in extremely high yields, respectively. This process was further applied to the total synthesis of an isoindolobenzazepine alkaloid, chilenine, by featuring the elaboration of the functionalized phthalimide derivative.

Copper(II)/Tin(II) Reagent for Allylation, Propargylation, Alkylation, and Benzylation of Disulfides and Elemental Sulfur: New Insight into the “Copper Effect”

Organic bromides and iodides react with diorganodisulfides in the presence of stannous chloride and catalytic cupric halide, giving rise to corresponding unsymmetrical sulfides. Similar reactions but with elemental sulfur provide trisulfides and tetrasulfides. The reactions proceed by copper thiolate as principal reactive intermediate.

Structure of 3,7-Diazabicyclo[3.3.1]nonane Complexes as the Basis of Creating New Metallocyclic Supramolecular Ensembles

The molecular and crystal structure of the complex of cupric bromide with 1,5-diphenyl-3,7-dimethyl-3,7-diazabicyclo[3.3.1]nonan-9-ones was studied. The geometry of the complexes of bispydines with cupric halides was shown to depend on the substituent at the nitrogen atom.

Copper(II)/Tin(II) Reagent for Allylation, Propargylation, Alkynylation, and Benzylation of Diselenides: A Novel Bimetallic Reactivity

Reactions of allyl, propargyl, benzyl, and alkynyl bromides with diorganodiselenides in the presence of stannous chloride and catalytic cupric halide result in the formation of corresponding unsymmetrical selenides in good to excellent yields via a novel dicopper(selenophenyl) intermediate.