Organic Chemistry Research
Volume:8 Issue: 2, Summer 2022

The advancements in cross-coupling chemistry are a considerably powerful tool for the synthesis of pharmaceutical molecules. The formation of catalytic carbon-heteroatom (C-X) and carbon-carbon (C-C) bonds is one of the important reactions in organic synthesis, which plays a key role in the synthesis of biologically active molecules, natural products, heterocycles, and useful compounds. Recently, there has been a significant increase in the development and advancement of environmentally friendly catalysts that serve as a suitable alternative to conventional metal catalysts. On the other hand, N-heterocyclic carbenes (NHC)–metal-based catalysts became suitable for performing a wide range of chemical transformations due to their unique spatial and electronic properties. The NHCs have received much attention as ligands due to their important properties. The present review aimed to discuss the recent advances in the application of NHCs in cross-coupling chemistry in the last six years. The present study focused on the catalytic application of NHCs in various cross-coupling reactions, such as Suzuki, Heck, Sonogashira, Hiyama, Kumada, Buchwald–Hartwig, Ullmann, and Chan. Moreover, some cross-coupling reactions by selective C-X cleavage catalyzed by NHCs with high catalytic activity were discussed. In addition, several chiral NHCs capable of catalyzing asymmetric cross-coupling reactions were reported. Finally, numerous green protocols for cross-coupling reactions catalyzed by functional and biocompatible NHCs under mild conditions were investigated. These protocols had advantages such as high-yield products, short time, cost-effectiveness, and high catalytic activity.

This study introduces Fe3O4@SiO2@CS@POCl2-x (NCP@ POCl2-x),an innovative and eco-friendly nanocatalyst, for the regioselective azidolysis of epoxides using NaN3. This process efficiently yields β-azido alcohols or β-amino alcohols, depending on the reaction conditions. In the presence of this catalyst, rapid azidation occurs, and the subsequent addition of water and application of heat efficiently produce β-amino alcohols. The catalyst is notable for its high yield and precise targeting of specific chemical sites (regioselectivity). Incorporating chitosan into the catalyst enhances its environmental friendliness, while surface hydroxyl and amine groups promote the smooth conversion of β-azido to β-amino alcohols via water incorporation in the mechanism and proton transfer during heating. This catalyst''s performance under mild conditions, with its excellent yield potential, underscores its significance in organic synthesis. Its ability to be easily recovered magnetically, its diverse composition, and efficient, clean reactions make it a vital tool for transforming epoxides.

The three-component Strecker reaction between 2-aminopyridine, aldehyde, and KCN in choline chloride-urea deep eutectic solvent (DES) was used for the synthesis of 2-aminoimidazopyridines. This reaction was carried out in simple conditions, and the reaction yields were very favorable. The use of the choline chloride-urea as an environmentally friendly solvent/catalyst is the main advantage of the presented synthesis method.

In this research GO was modified with 3-aminopropyl triethoxysilane (APTES-GO), and then was mixed with prepared (Ni0.7Zn0.3) Fe2O4 to obtain (Ni0.7Zn0.3)Fe2O4/APTES-GO nanocomposite. The composite was characterized by FT-IR, XRD, SEM, and EDX. Results confirmed the modification of GO with APTES, and the presence of Ni, Zn, and face-centered cubic (FCC) structure of Fe2O4. Finally, composite was used as an eco-friendly catalyst in one-pot synthesis of 2-amino-4H-Chromene via three-component reaction of malononitrile, aromatic aldehydes, and resorcinol. The obtained catalyst was recovered by an external magnetic field and reused several times without significant activity loss. Resulting 2-amino-4H-chromenes were purified and then characterized by FT-IR, 13C-NMR and 1H-NMR spectrums

2-Naphthol has undergone a specific oxidation process, leading to the formation of 2-hydroxy-1,4-naphthoquinone, a compound also recognized as Lawsone. In this research, NH2-MIL-125(Ti) was employed as a potent catalyst for photocatalytic reactions in conjunction with H2O2. The impact of NH2-MIL-125(Ti) on the reaction efficiency was prominently observed, leading to noticeable enhancements in the reaction yield.

Energy materials include substances used for the production, conversion, storage, and transmission of energy. Explosives as a part of ‘energetic materials’ are substances of which the internally stored huge chemical energy is liberated with a (self-sustaining) rapid and violent chemical reaction initiated with an outer stimulant; energetic materials include explosives, propellants, and pyrotechnics. Certain items such as natural fuels (fossil and synthetic fuels) burned in thermal power plants and motor vehicles, in conjunction with nuclear fuels (reacted in nuclear power plants) capable of emitting radioactive rays (alpha, beta, and gamma rays) and undergoing nuclear fission or fusion reactions have been deliberately excluded from this review. Additionally, either metals conducting heat or electricity with a reasonable resistance or superconductor materials transmitting electricity with practically no resistance (i.e. without loss) do not take place in this work. Therefore, energy materials have been tailored to include batteries and accumulators, fuel cells, photovoltaic and optoelectronic materials, and thermoelectric and piezoelectric materials, that convert and store chemical energy, radiation, heat, and mechanical energy in the form of electrical energy (or vice versa). This review aims to discuss the definitions, backgrounds, working principles, and applications of these systems to serve daily life. In addition to these, particular emphasis has been made on energetic materials, especially on explosives capable of liberating high amounts of heat and pressure in a rapid self-sustaining exothermic degradation reaction when appropriately stimulated.