Intramolecular cyclization of N-propargyl anilines: a new synthetic entry into highly substituted indoles

Recent Advances in the Application of Nanometal Catalysts for Glaser Coupling

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Synthesis of symmetrical 1,3-diynes from terminal alkynes through an oxidative process is generally called Glaser coupling. The classic Glaser coupling is catalyzed by copper salts under an atmosphere of molecular oxygen as an oxidant. Over the past years, different metal catalysts and oxidants were successfully used in this atom economical C-C coupling reaction. Moreover, several procedures for the preparation of unsymmetrical 1,3-diynes by coupling two different alkyne substrates have been developed. In this review, we will highlight the usefulness of transition metal nanoparticles as efficient catalysts in homo- and hetero-coupling of alkynes by hoping that it will be beneficial to the development of novel and extremely efficient catalytic systems for this fast-growing and important reaction.

Cycloaddition of atmospheric CO2 to epoxides under solvent-free conditions: a straightforward route to carbonates by green chemistry metrics

The conversion of carbon dioxide (CO2) into value-added organic compounds has received more and more attention over recent years, not only because this gas is one of the major anthropogenic greenhouse gases, but also because it has been regarded as an abundant, inexpensive, nontoxic, nonflammable, and renewable one-carbon (C1) resource. Along these lines, the synthesis of five-membered cyclic carbonates employing CO2 as a safe alternative to toxic reagents such as phosgene or its derivatives is of great interest because of their wide range of applications in organic synthesis. However, most of CO2 incorporation reactions into carbonates are carried out in toxic and non-recyclable organic solvents. Furthermore, these transformations usually proceed at elevated pressures or supercritical CO2 conditions. Recently, several catalytic systems have been developed that allow the synthesis of functionalized carbonates from the reaction of atmospheric CO2 with corresponding epoxides under solvent-free conditions. This review is an attempt to summarize the most important advances and discoveries in this interesting research arena. The review is divided into three major sections. The first section will discuss ionic liquid catalyzed coupling reactions. The second will cover organocatalyzed reactions. The third focuses exclusively on metal-catalyzed fixations. Notably, the third section has been classified based on the metal element that carries out the catalysis (i.e. copper, palladium, zinc).

Recent developments in decarboxylative cross-coupling reactions between carboxylic acids and N–H compounds

Carboxylic acids and their derivatives are ubiquitous compounds in organic chemistry, and are widely commercially available in a large structural variety. Recently, carboxylic acids have been frequently used as non-toxic and environmentally benign alternatives to traditional organohalide coupling partners in various carbon–carbon and carbon–heteroatom cross-coupling reactions. Along this line, several methods have been reported for the synthesis of nitrogen-containing organic compounds through decarboxylative cross-coupling reactions between carboxylic acids and N–H compounds. This review focuses on recent advances and discoveries on these reactions with special attention on the mechanistic aspects of the reactions.

Carboxylic acids and their derivatives are ubiquitous compounds in organic chemistry, and are widely commercially available in a large structural variety.

Solvent-free incorporation of CO2 into 2-oxazolidinones: a review

This review is an attempt to give an overview on the recent advances and developments in the synthesis of 2-oxazolidinone frameworks through carbon dioxide (CO₂) fixation reactions under solvent-free conditions. The cycloaddition of CO₂ to aziridine derivatives is discussed first. This is followed by carboxylative cyclization of N-propargylamines with CO₂ and three-component coupling of epoxides, amines, and CO₂. Finally, cycloaddition of CO₂ to propargylic alcohols and amines will be covered at the end of the review. The literature has been surveyed up until the end of 2018.

This review is an overview on the recent advances in the synthesis of 2-oxazolidinones through CO₂ fixation reactions under solvent-free conditions.

Arylhydrazines: novel and versatile electrophilic partners in cross-coupling reactions

Arylhydrazines are extremely valuable compounds in organic chemistry that are widely used for the synthesis of a variety of biologically active molecules such as indoles, indazoles, pyrazoles, aryltriazoles, β-lactams and quinazolines. These compounds have also been widely utilized as arylation agents in oxidative cross-coupling reactions. In this review, we will highlight the most important explorations and developments in the carbon-carbon and carbon-heteroatom (nitrogen, phosphorus, sulfur, and selenium) cross-coupling of arylhydrazines. The literature has been surveyed from 2001 to June 2018.

Decarboxylative cross-coupling reactions for P(O)-C bond formation

Phosphorus-containing compounds are one of the most important classes of organic compounds, which have wide applications in organic chemistry, medicinal chemistry, agricultural chemistry, and materials chemistry. In particular, organophosphorus compounds bearing a P(O)-C bond have attracted significant attention in recent decades due to their widespread biological and pharmacological activities. In this review, we will highlight the most important developments in the construction of P(O)-C bonds through decarboxylative C-P cross-coupling reactions. The literature has been surveyed from 2011 to May 2018.

Diaryl ethers synthesis: nano-catalysts in carbon-oxygen cross-coupling reactions

The diaryl ether moiety is not only prevalent in a significant number of natural products and synthetic pharmaceuticals but also widely found in many pesticides, polymers, and ligands. Ullmann-type cross-coupling reactions between phenols and aryl halides are regarded as one of the most important methods for the synthesis of this important and versatile structural motif. In recent years, the use of nano-sized metal catalysts in this coupling reaction has attracted a lot of attention because of these catalysts with their high surface-to-volume ratio, high surface energy, and reactive morphology allows for rapid C-O bond formation under mild and ligand-free conditions. In this review we will highlight the power of these catalysts in Ullmann-type C-O cross-coupling reactions.

Nanocatalysts for C–Se cross-coupling reactions

This mini review is an attempt to highlight the most important contributions toward the applications of nanocatalysts in carbon–selenium cross-coupling reactions with the emphasis on the mechanistic aspects of the reactions.