CuI Nanoparticles for C−N and C−O Cross Coupling of Heterocyclic Amines and Phenols with Chlorobenzenes

Synthesis of N-(α-fluorovinyl)azoles by the reaction of difluoroalkenes with azoles

A mild and versatile method for the construction of C-N bonds by the reaction of (2,2-difluorovinyl)arenes with various N-H-containing heterocycles in the presence of K3PO4 has been developed. The reaction proceeded efficiently at room temperature (25 °C) affording the (E)-N-α-fluorovinyl derivatives of azoles 3 in good to excellent yields with relatively high stereoselectivity.

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.

Nanoparticle mediated organic synthesis (NAMO-synthesis): CuI-NP catalyzed ligand free amidation of aryl halides

We have demonstrated the first ligand free CuI-nanoparticle catalyzed N-arylation of amides/cyclic amides in an ethylene glycol/2-propanol solvent system under mild conditions. This is further extended for one pot synthesis of benzimidazole, and quinazolinone via intermolecular amidation followed by cyclization.

A general route for synthesis of N-aryl phenoxazines via copper(i)-catalyzed N-, N-, and O-arylations of 2-aminophenols

A novel copper(i)-catalyzed tandem reaction ofN- andO-arylations was developed and a general route for synthesis ofN-aryl phenoxazinesviacopper-catalyzedN-,N-, andO-arylations of 2-aminophenols was established.

Synthesis of N-aryl substituted, five- and six-membered azacycles using aluminum-amide complexes

N-Aryl substituted, five- and six-membered azacycles, isoindoles and tetrahydroisoquinolines, were synthesized from the reaction of corresponding cyclic ethers (n = 1, 2) with dimethylaluminum-amide reagents.

Sonochemically synthesis of pyrazolones using reusable catalyst CuI nanoparticles that was prepared by sonication

A simple and green process to prepare copper iodide in nano scale via sonication was carried out. Subsequently, this nanoparticles was used as an efficient catalyst for the synthesis of 2-aryl-5-methyl-2,3-dihydro-1H-3-pyrazolones via four-component reaction of hydrazine, ethyl acetoacetate, aldehyde and β-naphthol in water under ultrasound irradiation. The combinatorial synthesis was attained for this procedure with applying ultrasound irradiation while making use of water as green ambient. Simple work-up, excellent yield of products and short reaction times are some of the important features of this protocol. Notably, this catalyst could be recycled and reused for five times without noticeably decreasing the catalytic activity.

Copper nanoparticle-catalyzed carbon-carbon and carbon-heteroatom bond formation with a greener perspective

The carbon-carbon and carbon-heteroatom bond formations constitute the backbone of organic synthesis and have been widely used in the synthesis of natural products and useful compounds. Because of growing environmental concern, more attention has been focussed on the development of greener methods. Copper is environment-friendly and comparatively inexpensive. Although the use of copper salts in catalysis has been known since the last century, this area of research has been less explored compared to other metals, such as palladium, magnesium, and zinc. This review highlights the general features of nanoparticles as catalysts with particular reference to copper and the recent developments in the copper(0) nanoparticle-catalyzed C(aryl)-C(aryl/alkynyl), C(aryl)-N, C(aryl)-O, C(aryl)-S, and C(aryl)-Se bond formations and related reactions. The mechanisms of the reactions have been outlined and discussed with respect to the active catalytic species and possible intermediates. The scope, limitations, and green aspects of the reactions have also been highlighted. The convenient methods of preparation of copper nanoparticles and their characterization are described.

Recyclable heterogeneous copper oxide on alumina catalyzed coupling of phenols and alcohols with aryl halides under ligand-free conditions

An efficient alumina-supported CuO-catalyzed O-arylation of phenols and aliphatic alcohols with various aryl as well as heteroaryl halides under ligand-free conditions are reported. This protocol provides a variety of diaryl ether and bis-diaryl ether motifs by reacting different aryl/aliphatic halides with differently substituted phenols and saturated alcohols in the presence of a catalytic amount of CuO on alumina and KOH as a base at moderate temperature under nitrogen atmosphere. The described methodology is simple, straightforward and efficient to afford the cross-coupled products in high yields under ligand-free conditions. The explored catalyst is inexpensive, air-stable and recyclable up to three cycles.

Ligand-free CuO nanospindle catalyzed arylation of heterocycle C-H bonds

CuO nanospindles have been developed to efficiently catalyze the direct arylation of heterocycle C-H bonds with moderate to excellent yields. This reaction can be applied to heterocycles such as benzoxazole, benzothiazole, and 1-methylbenzimidazole in the presence of a more environmentally friendly inorganic base like K(2)CO(3) under ligand-free catalytic conditions. In addition, the catalyst can be recycled and reused without any significant decrease in catalytic activity.