Palladium on Calcium Carbonate Combined to 2-Hydroxypropyl-α/β-cyclodextrins: A Selective Catalytic System for Aqueous Heck Coupling and Hydroarylation

A Focussed Analysis of β-cyclodextrins for Quinoxaline Derivatives Synthesis

Abstract:

Cyclodextrins (CDs), which are a type of cyclic oligosaccharides, are widely used in supramolecular chemistry. For example, they can be used to encapsulate volatile compounds, such as drugs, within their hydrophobic cavity. This encapsulation reduces the volatility of the compounds and helps to retain their desired properties. Due to its extraordinary properties, cyclodextrins have been utilized as catalysts in numerous organic synthesis processes. An intrinsic objective of organic chemists is to optimize the efficacy of organic synthesis through the mitigation of chemical waste and energy expenditure. Utilizing water as a green solvent is, therefore, economical, environmentally sustainable, and secure. It appears that employing water in conjunction with a recyclable catalyst is the most effective method for supramolecular catalysis. As a consequence, we focused this review on the use of water as a solvent and cyclodextrin as a polymer catalyst to produce quinoxaline derivatives in an environmentally friendly and sustainable manner.

Prospects and Applications of Palladium Nanoparticles in the Cross-coupling of (hetero)aryl Halides and Related Analogues

Discovering efficient methods for the formation of carbon-carbon bonds is a central ongoing theme in organic synthesis. Cross-coupling reactions catalysed by metal nanoparticles are attractive alternatives to the traditional use of metal counterparts due to the catalytic tunability, selectivity, recyclability and reusability of the nanoparticles. The ongoing search for sustainable processes demands that reusable and environmentally benign catalysts are used. While the advantages of nanoparticles catalysts over bulk catalysts cannot be overemphasised, the problem of sintering, agglomeration and leaching are drawbacks to their full industrial applications. Hence, efforts are being made towards advancing the efficiency of the catalytic nanoparticle systems over the years. This review presents the progress, the challenges and the prospects of palladium nanoparticle with focus on Heck, Suzuki, Hiyama and Sonogashira cross-coupling reactions involving (hetero) aryl halides and the analogues.

Organic Synthesis: New Vistas in the Brazilian Landscape

In this overview, we present our analysis of the future of organic synthesis in Brazil, a highly innovative and strategic area of research which underpins our social and economical progress. Several different topics (automation, catalysis, green chemistry, scalability, methodological studies and total syntheses) were considered to hold promise for the future advance of chemical sciences in Brazil. In order to put it in perspective, contributions from Brazilian laboratories were selected by the citations received and importance for the field and were benchmarked against some of the most important results disclosed by authors worldwide. The picture that emerged reveals a thriving area of research, with new generations of well-trained and productive chemists engaged particularly in the areas of green chemistry and catalysis. In order to fulfill the promise of delivering more efficient and sustainable processes, an integration of the academic and industrial research agendas is to be expected. On the other hand, academic research in automation of chemical processes, a well established topic of investigation in industrial settings, has just recently began in Brazil and more academic laboratories are lining up to contribute. All these areas of research are expected to enable the future development of the almost unchartered field of scalability.

Green synthesis of palladium nanoparticles via branched polymers: a bio-based nanocomposite for C–C coupling reactions

Renewable and sustainable CMH was the natural ligand for CMH–Pd(0) nanocomposite which was as an efficient and recyclable catalyst for Heck reaction.

Highly water-dispersible magnetite nanoparticle supported-palladium–β-cyclodextrin as an efficient catalyst for Suzuki–Miyaura and Sonogashira coupling reactions

A novel highly water-dispersible and recoverable magnetite supported palladium–β-cyclodextrin complex as efficient catalyst in Suzuki–Miyaura and Sonogashira carbon–carbon coupling reactions.

A ternary catalytic system for the room temperature Suzuki-Miyaura reaction in water

The formation of Pd(0) in the absence of any classical reducing agent in a medium containing Mg²⁺/Al³⁺ layered double hydroxide (LDH) and N,N-dimethylformamide was evidenced. XRD analysis showed the presence of crystalline phases of palladium in the Pd/LDH composite. Suzuki-Miyaura reactions in aqueous medium were carried out at room temperature, and good yields were obtained with bromoarenes and iodoarenes using the ternary system LDH-Pd-CD (cyclodextrin) as catalyst.