Amino acid-mediated Goldberg reactions between amides and aryl iodides

Reusable cobalt-copper-catalyzed cross-coupling of (hetero)aryl halides with primary amides under air: investigating a new Co0/CoII-based catalytic cycle

We report an efficient ligand-free cobalt-copper-catalyzed cross-coupling reaction of aryl halides with primary amides and also investigate a new Co0/CoII-based catalytic cycle for this transformation. This reaction successfully couples a wide range of aryl and heteroaryl halides (including chlorides, bromides, and iodides) with various aryl, heteroaryl, and aliphatic primary amides in air under solvent-minimized conditions. This cost-effective method efficiently produces the desired cross-coupling products (N-arylamides) in good to excellent yields, showcasing a broad substrate scope (51 examples) and tolerance to many sensitive functional groups (including heterocycles). This protocol requires no conventional work-up and can be performed without the need for strict inert conditions. The established method is also suitable for gram-scale synthesis. Importantly, the catalyst is environmentally benign, inexpensive, and can be reused several times with insignificant loss of catalytic activity. A series of experiments, including UV spectroscopy, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and cyclic voltammetry (CV), were carried out to determine the oxidation state of the active catalytic species, and a radical clock experiment using a radical probe was conducted to examine the reaction mechanism. The experiments support the proposed novel mechanism and eliminate the possibility of a radical-based pathway.

Reusable Iron-Copper Catalyzed Cross-Coupling of Primary Amides with Aryl and Alkyl Halides: Access to N-Arylamides as Potential Antibacterial and Anticancer Agents

We present, for the first time, an efficient ligand-free iron-copper catalyzed cross-coupling reaction involving a variety of aryl, heteroaryl halides (including chlorides, bromides, and iodides), and alkyl bromides with diverse aryl and aliphatic primary amides, conducted under solvent-minimized conditions. This economically competitive protocol successfully yielded the corresponding cross-coupling products, N-arylamides and N-alkylamides, in good to excellent yields with broad substrate scope (65 examples) and tolerance to several sensitive functionalities (including heterocycles). No conventional work-up is required for this protocol, and the developed method is applicable for gram-scale synthesis. Notably, the catalyst is inexpensive, environmentally friendly, and can be reused at least four times with minimal loss of catalytic activity. A series of experiments, including X-ray photoelectron spectroscopy (XPS), UV spectroscopy, cyclic voltammetry (CV), electron paramagnetic resonance (EPR), and X-ray diffraction (XRD) were conducted to identify the oxidation state of active catalytic species and radical clock experiment was performed using a radical probe to investigate the reaction mechanism. Furthermore, we evaluated the antibacterial and anticancer properties of selected synthesized products (3 ii, 3 xii, and 3 xxxx) in-vitro. The results indicated that the prepared compounds exhibited promising antibacterial and anticancer activities (MTT and Molecular Docking).

Metal-catalyzed reactions for the C(sp2)–N bond formation: achievements of recent years

The review deals with the main catalytic methods for the C(sp2)–N bond formation, including Buchwald–Hartwig palladium-catalyzed amination of aryl and heteroaryl halides, renaissance of the Ullmann chemistry, i.e., the application of catalysis by copper complexes to form the carbon–nitrogen bond, and Chan–Lam reactions of (hetero)arylboronic acids with amines. Also, oxidative amination with C–H activation, which has been booming during the last decade, is addressed. Particular attention is paid to achievements in the application of heterogenized catalysts.

The bibliography includes 350 references.

LiCl-promoted amination of β-methoxy amides (γ-lactones)

An efficient and mild method has been developed for the amination of β-methoxy amides (γ-lactones) including natural products michelolide, costunolide and parthenolide derivatives by using lithium chloride in good yields. This reaction is applicable to a wide range of substrates with good functional group tolerance. Mechanism studies show that the reactions undergo a LiCl promoted MeOH elimination from the substrates to form the corresponding α,β-unsaturated intermediates followed by the Michael addition of amines.

The amination of β-methoxy amides (γ-lactones) including natural products michelolide, costunolide and parthenolide derivatives were first developed by using lithium chloride.

Bimetallic Catalyzed N-arylation Used in Synthesis of Novel β-carbolines Derivatives

Background:

Natural occurring β-Carbolines alkaloids are abundant in the plant kingdom or other organisms, and they were found to possess good antitumor activity through multiple mechanisms. Based on previous summarized SARs of β-carboline derivatives, the modification on pyridine ring would have a great impact on their antitumor activities. Therefore, we plan to synthesized arylated β-carboline-3-amides to find more valuable β-Carbolines derivatives.

Methods:

A novel bimetallic Pd(OAc)2/AgOAc catalyst system was developed for the amidation of aryl iodides under acid condition. A series of N-arylated β-carbolines derivatives were synthesized using this method. The structures of these compounds were confirmed by 1H NMR, 13C NMR and HRMS, and their in vitro antiproliferative activity was investigated against HepG2 and Hela tumor cell lines by MTT assay.

Results:

Eleven N-arylated β-carboline-3-amides were synthesized using this bimetallic catalyzed method in 58-98% yields. These synthesized N-arylated compounds showed no antiproliferative activity at 20 μM.

Conclusion:

We have discovered an efficient and bimetallic catalytic system allowing the Narylation of secondary acyclic amides. This is the first report that N-arylation of aliphatic secondary acyclic amides under acid condition.

An efficient and easily-accessible ligand for Cu(i)-catalyzed azide–alkyne cycloaddition bioconjugation

A novel ligand (6) for copper-catalyzed azide–alkyne cycloaddition (CuAAC) in bioconjugation has been developed.

Iodoferrocene as a partner inN-arylation of amides

A general copper-promoted amidation of iodoferrocene is described toward original scaffolds that can be further functionalized by cross-coupling reactions.

CuCl heterogenized on metformine-modified multi walled carbon nanotubes as a recyclable nanocatalyst for Ullmann-type C–O and C–N coupling reactions

Herein, a novel MWCNTs-Met/CuCl nanocatalyst synthesis method by metformine covalent grafting on the surface of carbon nanotubes and subsequent coordination with a CuCl catalyst is described.

Highly efficient asymmetric construction of novel indolines and tetrahydroquinoline derivatives via aza-Barbier/C–N coupling reaction

An efficient approach towards stereoselective synthesis of chiral indolines and tetrahydroquinolines via Zn-mediated allylation of chiral-N-tert-butanesulfinyl imines and intramolecular C–N cross-coupling is described.

Applications of Palladium-Catalyzed C-N Cross-Coupling Reactions

Pd-catalyzed cross-coupling reactions that form C–N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C–N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.

Green alternative solvents for the copper-catalysed arylation of phenols and amides

The use of alkyl acetates as green organic solvents for the Cu-catalysed arylation of phenols and amides is reported.

Copper/N,N-dimethylglycine catalyzed goldberg reactions between aryl bromides and amides, aryl iodides and secondary acyclic amides

An efficient and general copper-catalyzed Goldberg reaction at 90–110 °C between aryl bromides and amides providing the desired products in good to excellent yields has been developed using N,N-dimethylglycine as the ligand. The reaction is tolerant toward a wide range of amides and a variety of functional group substituted aryl bromides. In addition, hindered, unreactive aromatic and aliphatic secondary acyclic amides, known to be poor nucleophiles, are efficiently coupled with aryl iodides through this simple and cheap copper/N,N-dimethylglycine catalytic system.

Copper catalysed Ullmann type chemistry: from mechanistic aspects to modern development

Cu-catalysed arylation reactions devoted to the formation of C-C and C-heteroatom bonds (Ullmann-type couplings) have acquired great importance in the last decade. This review discusses the history and development of coupling reactions between aryl halides and various classes of nucleophiles, focusing mostly on the different mechanisms proposed through the years. Selected mechanistic investigations are treated more in depth than others. For example, evidence in favour or against radical mechanisms is discussed. Cu(I) and Cu(III) complexes involved in the Ullmann reaction and N/O selectivity in aminoalcohol arylation are discussed. A separate section has been dedicated to the synthesis of heterocyclic rings through intramolecular couplings. Finally, recent developments in green chemistry for these reactions, such as reactions in aqueous media and heterogeneous catalysis, have also been reviewed.

Direct N-cyclopropylation of secondary acyclic amides promoted by copper

The N-cyclopropylation of aromatic and aliphatic secondary acyclic amides, known to be poor nucleophiles, has been accomplished using a simple and cheap copper system. The corresponding tertiary acyclic amides, which constitute a wide family of biologically active compounds, have been obtained in good to excellent yields.