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Topic Review
The Asymmetric Hydroarylation of Activated Aryl Portions
Hydroarylation reactions enable the formation of new Csp2–Csp3 or Csp2–Csp2 bonds using aromatic substrates. Its outcome is described as the addition of hydrogen and an aryl group to an unsaturated moiety, resulting in the functionalization of the aromatic Csp2–H bond. Hydroarylation reactions can occur by a direct functionalization via insertion of an unsaturated compound or with the use of pre-activated aryl substrates, usually aryl-iodides or aryl-boronated. Below are reported some example from the scientific production of the last 10 years about the asymmetric hydroarylation of activated aryl portions. Nickel and palladium turned out to be the more-employed metals. 
  • 483
  • 07 Dec 2022
Topic Review
Synthesis of Heteroaromatic Hybrid Chalcones
Chalcones continue to occupy a venerated status as scaffolds for the construction of a variety of heterocyclic molecules with medicinal and industrial properties. Syntheses of hybrid chalcones featuring heteroaromatic components, especially those methods utilizing green chemistry principles, are important additions to the preparative methodologies for this valuable class of molecules. 
  • 477
  • 21 Aug 2023
Topic Review
The Lewis Acid System
Cycloketones can be oxidized to lactones using molecular oxygen, peroxy acids, or hydrogen peroxide as an oxidant. Hydrogen peroxide is one of the environmental oxidants. Because of the weak oxidation ability of hydrogen peroxide, Bronsted acids and Lewis acids are used as catalysts to activate hydrogen peroxide or the carbonyl of ketones to increase the nucleophilic performance of hydrogen peroxide. The catalytic mechanisms of Bronsted acids and Lewis acids differ in the Baeyer–Villiger oxidation of cyclohexanone with an aqueous solution of hydrogen peroxide as an oxidant.
  • 475
  • 02 Feb 2023
Topic Review Peer Reviewed
Photoremovable Protecting Groups
Photoremovable protecting groups (PPGs) (also often called photocages in the literature) are used for temporary inactivation of biologically active substrates. By photoirradiation the PPG could be cleaved off and the biological activity could be restored on-demand, with a high spatiotemporal precision. The on-site liberation of the biologically active substrate could be exploited for studying dynamic biological processes or for designing targeted pharmacological interventions in vitro or in vivo. Several chemical scaffolds have been described and tested as PPGs, operating at different wavelengths. The scope of potential substrates is very broad, spanning from small molecules to proteins. In a wider context, PPGs could be used for the design of various light-responsive materials as well, for diverse applications. 
  • 474
  • 21 Oct 2022
Topic Review
Selected Fungal Natural Products with Antimicrobial Properties
Natural products (NPs) are a very rich source of antimicrobial drugs. They constitute more than two-thirds of clinically used antibiotics and half of anticancer drugs. Fungal natural products and their effects have been known to humankind for hundreds of years. Their later medicinal applications, followed by the discovery of the first class of antibiotics, penicillins and other drugs of fungal origin, such as peptidic natural products, terpenoids or polyketides, have altered the historically negative reputation of fungal “toxins”. 
  • 473
  • 21 Jul 2022
Topic Review
Versatile Fluorine-Containing Building Blocks
The development of diversity-oriented synthesis based on fluorine-containing building blocks has been one of the hot research fields in fluorine chemistry. β-CF3-1,3-enynes, as one type of fluorine-containing building blocks, have attracted more attention due to their distinct reactivity. Numerous value-added trifluoromethylated or non-fluorinated compounds which have biologically relevant structural motifs, such as O-, N-, and S-heterocycles, carboncycles, fused polycycles, and multifunctionalized allenes were synthesized from these fluorine-containing building blocks.
  • 473
  • 30 Dec 2022
Topic Review
Deconstructive and Divergent Synthesis of Bioactive Natural Products
Deconstructive synthesis, namely building new, challenging structures through bond cleavage of easily accessible moieties, has emerged as a useful design principle in synthesizing bioactive natural products. Divergent synthesis, namely synthesizing many natural products from a common intermediate, can improve the efficiency of chemical synthesis and generate libraries of molecules with unprecedented structural diversity.
  • 471
  • 29 Aug 2023
Topic Review
Photocatalytic Transformation of Biomass and Biomass Derived Compounds
Biomass and biomass-derived compounds have become an important alternative feedstock for chemical industry. They may replace fossil feedstocks such as mineral oil and related platform chemicals. These compounds may also be transformed conveniently into new innovative bioactive products, for example, for the medicinal or the agrochemical domain.
  • 464
  • 27 Jun 2023
Topic Review
Meso-Formylporphyrins
Insertion of the formyl group into porphyrins is a primary functionalization of the tetrapyrrole ring, opening opportunities for further transformations including, but not limited to, Wittig, Grignard, McMurry, cycloaddition, Knoevenagel reactions, and Schiff bases preparation.
  • 463
  • 23 Aug 2023
Topic Review
H2S Sensors
Hydrogen sulfide (H2S) is an essential signaling gas within the cell, and its endogenous levels are correlated with various health diseases such as Alzheimer’s disease, diabetes, Down’s syndrome, and cardiovascular disease. Because it plays such diverse biological functions, being able to detect H2S quickly and accurately in vivo is an area of heightened scientific interest.
  • 463
  • 06 May 2023
Topic Review
Natural 4-Hydroxy-2-pyrones
4-Hydroxy-2-pyrones as polyketides are widespread in Nature and possess versatile bioactivity that makes them an attractive target for synthesis and modification. Also these pyrones bear several electrophilic and nucleophilic centers that determine their application in organic synthesis.
  • 461
  • 02 Jan 2024
Topic Review
Magnetic Catalysts in Ullmann-Type N-Arylation Reactions
Ullmann-type C–N heterocoupling reactions have been applied for the syntheses of N-arylated amines. Transition metal-catalyzed N-arylations have been recognized as particularly efficient procedures for the preparation of nitrogen-containing aromatic systems. These reactions typically carried out under optimized conditions, have also been found to be suitable for the synthesis of complex molecules with other functional groups, including natural products, drugs, or pharmaceuticals. Most importantly, copper-catalyzed N-arylations have been studied and employed in the total synthesis of biologically active compounds. The construction of fused N-heterocyclic compounds also remained the subject of extensive research because of their potential applications in drug discovery and the development of functional materials. 
  • 459
  • 02 Aug 2023
Topic Review
Flexible Electrochromic Materials
The application potential of flexible electrochromic materials for wearable devices, smart textiles, flexible displays, electronic paper, and implantable biomedical devices is enormous. These materials offer the advantages of conformability and mechanical robustness, making them highly desirable for these applications.
  • 453
  • 07 Jul 2023
Topic Review
Functionalization and Applications
Microcrystalline Cellulose (MCC) is an isolated, colloidal crystalline portion of cellulose fibers, and it is a valuable alternative to non-renewable fossil-based materials. It is used for a large plethora of different fields, such as composites, food applications, pharmaceutical and medical developments, and cosmetic and material industries. The interest of MCC has also been driven by its economic value. In the last decade, particular attention has been driven to the functionalization of its hydroxyl groups to expand the field of applications of such biopolymer. 
  • 438
  • 17 Mar 2023
Topic Review
Near-Infrared Emission Materials with “Heavy Metal-Free” Organic Compounds
Organic/polymer light-emitting diodes (OLEDs/PLEDs) have attracted a rising number of investigations due to their promising applications for high-resolution fullcolor displays and energy-saving solid-state lightings. Near-infrared (NIR) emitting dyes have gained increasing attention for their potential applications in electroluminescence and optical imaging in optical tele-communication platforms, sensing and medical diagnosis in recent decades. And a growing number of people focus on the “heavy metal-free” NIR electroluminescent materials to gain more design freedom with cost advantage. 
  • 434
  • 17 Feb 2023
Topic Review
Sequential Reactions of α-Aminoalkynes with Carbonyls
Sequential reactions of aminoalkynes represent a powerful tool to easily assembly biologically important polyfunctionalized nitrogen heterocyclic scaffolds. Metal catalysis often plays a key role in terms of selectivity, efficiency, atom economy, and green chemistry of these sequential approaches.
  • 427
  • 26 Jun 2023
Topic Review
Antibacterial Activities of 1,2,3-Triazolium Salts
1,2,3-Triazolium salts have demonstrated significant potential in the fields of medicine and agriculture, exhibiting exceptional antibacterial, antifungal, anticancer, and antileishmanial properties. Moreover, these salts can be utilized as additives or components to produce nano- and fiber-based materials with antibacterial properties. 
  • 427
  • 17 Jul 2023
Topic Review
Spiro-Flavonoids in Nature
The research collects 65 unique structures, including spiro-biflavonoids, spiro-triflavonoids, spiro-tetraflavonoids, spiro-flavostilbenoids, and scillascillin-type homoisoflavonoids. Scillascillin-type homoisoflavonoids comprise spiro[bicyclo[4.2.0]octane-7,3′-chromane]-1(6),2,4-trien-4′-one, while the other spiro-flavonoids contain either 2H,2′H-3,3′-spirobi[benzofuran]-2-one or 2′H,3H-2,3′-spirobi[benzofuran]-3-one in the core of their structures. Spiro-flavonoids have been described in more than 40 species of eight families, including Asparagaceae, Cistaceae, Cupressaceae, Fabaceae, Pentaphylacaceae, Pinaceae, Thymelaeaceae, and Vitaceae. The possible biosynthetic pathways for each group of spiro-flavonoids are summarized in detail. Anti-inflammatory and anticancer activities are the most important biological activities of spiro-flavonoids, both in vitro and in vivo.
  • 424
  • 25 Jul 2023
Topic Review
Tellurophenes
Tellurophenes are the tellurium analogue of thiophenes and selenophenes.
  • 423
  • 12 Oct 2022
Topic Review
Structures of Biphenarenes
In 2015, Li and co-workers synthesized a new macrocyclic host named biphenarenes, which including basic biphen[n]arenes, functional biphen[n]arenes, and cage compounds. Typically, biphenarenes are made up of 4,4′-biphenol or 4,4′-biphenol ether units linked by methylene bridges at the 3- and 3′-positions. The synthesis of biphenarenes is based on the linking of reaction modules to form macrocycles by Friedel–Crafts alkylation. In addition, modular synthetic strategy is a versatile method for the synthesis of biphenarenes, which can increase the cavity sizes by changing the structural units. For example, the cavity sizes of biphenarenes can be easily increased using long and rigid structural units or increasing the number of structural units. Meanwhile, gram-scale synthesis of biphenarenes is easily achieved in a laboratory. The purification of biphenarenes can be achieved by column chromatography and recrystallization. Furthermore, biphenarenes are easy to prepare since they can be obtained by a one-step condensation reaction using commercial reagents. Biphenarenes show good performance in adsorptive separation, sensing and drug delivery, and have broad application prospects in chemistry, biology, materials science and other fields.
  • 422
  • 13 Jun 2023
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