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Recently, bulky alkaline earth (Ae=Mg, Ca, Sr, Ba) metal amide complexes AeN"2 (N"=N[Si(iPr)3]2) are shown to be active for catalyzing the hydrogenation of unactivated alkenes and arenes, presumably via the monomer N"AeH as catalyst. In sharp contrast, our extensive DFT calculations disclose that the double Ae−H−Ae bridged dimer (N"AeH)2 is kinetically more favorable in catalytic hydrogenation with H2, although rate‐limited by the initial hydrogenolysis of AeN"2 to form the monomer N"AeH. [ABSTRACT FROM AUTHOR]

Half‐sandwich Ru(II)‐ and Os(II)‐arene complexes have great potential for catalytic and biological applications. The possibility of fine‐tuning their chemical reactivity by including modifications in the ligands around the metal adds to their many advantages. However, structural modifications at the η6‐bound arene have had significant synthetic limitations, particularly in the design of Os(II)‐tethered complexes. For the first time, we have employed a practical C(sp3)‐C(sp2) coupling to obtain 28 new Ru(II) and Os(II) η6‐arene half‐sandwich complexes with a wide variety of arene functionalities, including those that enable the formation of tether rings, such as quinoline, and coumarin. The introduction of novel functional groups at the arene in Ru(II)‐ and Os(II) half‐sandwich complexes can broaden the synthetic scope of this type of organometallic complexes, and help to take full advantage of their structural diversity, for example, in intracellular catalysis. [ABSTRACT FROM AUTHOR]

In this contribution, we present "Birch‐type", and other reductions of simple arenes by the potassium salt of an anionic magnesium dinitrogen complex, [{K(TCHPNON)Mg}2(μ‐N2)] (TCHPNON=4,5‐bis(2,4,6‐tricyclohexylanilido)‐2,7‐diethyl‐9,9‐dimethyl‐xanthene), which acts as a masked dimagnesium(I) diradical in these reactions. This reagent is non‐hazardous, easy‐to‐handle, and in some cases provides access to 1,4‐cyclohexadiene reduction products under relatively mild reaction conditions. This system works effectively to reduce benzene, naphthalene and anthracene through magnesium‐bound "Birch‐type" reduction intermediates. Cyclohexadiene products can be subsequently released from the magnesium centres by protonolysis with methanol. In contrast, the reduction of substituted arenes is less selective and involves competing reaction pathways. For toluene and 1,3,5‐triphenylbenzene, the structural authentication of "Birch‐type" reduction intermediates is conclusive, although the formation of corresponding 1,4‐cyclohexadiene derivatives was low yielding. Reduction of anisole did not yield an isolable "Birch‐type" intermediate, but instead gave a C−O activation product. Treating triphenylphosphine with [{K(TCHPNON)Mg}2(μ‐N2)] resulted in the extrusion of both biphenyl and dinitrogen to afford a magnesium(II) phosphanide [{K(TCHPNON)Mg(μ‐PPh2)}2]. Reduction of fluorobenzene proceeded via C−F activation of the arene, and isolation of the magnesium(II) fluoride [{K(TCHPNON)Mg(μ‐F)}2]. Finally, the two‐electron reduction of 1,3,5,7‐cyclooctatetraene (COT) with [{K(TCHPNON)Mg}2(μ‐N2)] yielded a complex, [{K(TCHPNON)Mg}2(μ‐COT)], incorporating the aromatic dianion (COT2−). [ABSTRACT FROM AUTHOR]

A nitrosonium catalyzed bromination of electron‐rich arenes has been developed, using bromide salts as bromine sources, oxygen gas as a terminal oxidant and Brønsted acids (sulfuric acid, TFA or HBr). This arene bromination process is free of transition metals, proceeding in acetic acid and under mild temperatures (25–50 °C) to give brominated arenes with good to excellent yields. Our mechanistic studies indicated that this oxidative bromination of arenes reaction is catalyzed by nitrosnium ion (NO+), without the involvement of Br2 or Br+. The kinetic isotope effect of this reaction was measured using pentadeuteriophenyl phenyl ether (kH/kD=1.1). [ABSTRACT FROM AUTHOR]

A catalyst‐free 1,2‐diborylation of aryllithium with tetra(o‐tolyl)diborane(4) has been achieved, giving a series of 1,2‐diborylaryl lithium species in excellent yields under mild reaction conditions, which leads to 1,2‐di(tolyl)borylarenes in 60–91 % yields upon treatment with the hydride‐abstracting reagent. In these transformations, one sp2 C−H of arene is activated and both boryl units are utilized to build two new (sp2)C−B bonds. This represents a new strategy for selective arene diborylation. Density functional theory (DFT) calculations suggest that an aromatic nucleophilic substitution is a key step in the formation of the products. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons consisting of two or three rubicene substructures were designed as π‐conjugated compounds embedding five‐membered rings. The target compounds with t‐butyl groups were synthesized by the Scholl reaction of precursors consisting of 9,10‐diphenylanthracene units, even though a partially precyclized precursor was required for the synthesis of the trimer. These compounds were isolated as stable and dark blue solids. Single‐crystal X‐ray analysis and DFT calculations revealed the planar aromatic framework of these compounds. In the electronic spectra, the absorption and emission bands were considerably red‐shifted compared with those of the reference rubicene compound. In particular, the emission band of the trimer extended to the near‐IR region while retaining the emissive property. The narrowed HOMO‐LUMO gap with the extension of the π‐conjugation was confirmed by cyclic voltammetry and DFT calculations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Various Lewis acids catalyse the electrophilic amidation of arenes in acetic acid. • O-acetyl acetohydroxamic is used as atom-efficient amidating agent. • Kinetic and spectroscopic data point towards electrophilic aromatic substitution. Electrophilic arene C H amination constitutes an intrinsically more atom- and step-economical pathway towards arylamines than C X → C N methods. However, most literature examples are restricted to arenes with extensive directing groups (DG) and/or nitrogen coupling partners with large leaving groups (LG). Moreover, only few cases of EAs using cheap metals (e.g. , Fe) have been reported. Herein, we demonstrate the catalytic activity of various Lewis acids in the electrophilic amidation of simple arenes with O -acetyl acetohydroxamic acid in acetic acid. With 5 mol% FeIII(citrate)·H 2 O, up to 27 % yield was achieved, whereas 5 mol% BiCl 3 gave up to 31 % yield. Instability of the amidation agent and product inhibition were identified as the yield-limiting factors. The observed regioselectivity, as well as kinetic and spectroscopic data suggest an electrophilic aromatic substitution mechanism, in which acetic acid and the Lewis acid generate a highly electrophilic species from AcNHOAc. [ABSTRACT FROM AUTHOR]

The factors determining the catalytic performance of a recently discovered system for direct intermolecular alkyne hydroarylations, comprising a gold(I) complex of general formula LAuX (L = neutral ligand; X = weakly coordinating counteranion) and an ionic liquid as solvent, have been investigated. In particular, the effect of the ionic liquid anion, cation, and of the electronic and steric properties of the neutral ligand L have been considered. The results of the investigation shed some light in particular on the role of the anion, which is multiform and can potentially influence the catalytic performance in many respects, and on the role of the neutral ligand, which should be a relatively poor electron donor but not so much as to compromise the stability of the catalyst. Knowledge of the factors affecting catalytic performance will speed up the optimization of this catalytic system, in the case of direct alkyne hydroarylations with different substrates, and will also facilitate the extension of its application to other reactions. [ABSTRACT FROM AUTHOR]

• A new series of arene Ru(II) complexes containing aromatic coumarin derivative ligands have been reported. • 3-acetyl coumarin derivatives with ruthenium dimers resulted in neutral mononuclear complexes. • Octahedral geometry was confirmed by single crystal XRD. • Ligands (1, 3 and 4) and complex 7 showed highest antioxidant activity. • DFT calculations establish that the calculated values are in good agreement with the experimental data. The reaction of [(arene)RuCl 2 ] 2 with coumarin hydrazone ligands in methanol yielded neutral chelating mononuclear N∩O metal complexes having the general formula [(arene)Ru(L)Cl] where arene = p -cymene, benzene; and L = 3‑hydroxy-N'-(1-(2-oxo-2H-chromen-3-yl)ethylidene)-2-naphthohydrazide (L1), 3‑hydroxy-N'-(1-(7‑methoxy-2-oxo-2H-chromen-3-yl)ethylidene)-2-naphthohydrazide (L2), (E)-N'-(1-(6‑bromo-2-oxo-2H-chromen-3-yl)ethylidene)-3‑hydroxy-2-naphthohydrazide (L3) and 3‑hydroxy-N'-(1-(3-oxo-3H-benzo[f]chromen-2-yl)ethylidene)-2-naphthohydrazide (L4)}. All complexes (1–8) were fully characterized by spectroscopic techniques like IR, UV–Vis, NMR and ESI-MS spectral methods. The solid-state molecular structures of the three complexes were determined using a single-crystal X-ray diffraction study. The studies revealed that the ligands binding mode to the ruthenium metal centers is through the azomethine nitrogen and the imidolate oxygen forming a five-membered chelating ring. All the complexes and the ligands were screened for antibacterial and antioxidant activity studies. Some of the complexes exhibited antioxidant activity that is more prominent than their respective ligands. [Display omitted] [ABSTRACT FROM AUTHOR]

Dearomative photocycloaddition reactions offer a powerful strategy to construct sp3-rich 3D frameworks adorned with diverse functionalities from readily available 2D feedstocks. This method leverages visible light to drive cascades of energy transfer (EnT) or single electron transfer (SET) mediated by organic or transition metal photosensitizers (e.g., ruthenium (Ru), chromium (Cr), and iridium (Ir)). These reactions represent a compelling alternative to harsh thermal methods, enabling the formation of complex molecules under mild conditions. The inherent potential for dearomatizing polycyclic arenes and heteroarenes makes dearomative cycloaddition a highly sought-after synthetic approach. It stands as a rival to nature-inspired synthesis, allowing for the creation of intricate scaffolds in the lab through the synergistic interplay of visible light and transition metal complexes. Inspired by the prowess of transition metal-mediated dearomative cycloadditions, this comprehensive review delves into the progress made over the past decade in photocatalytic dearomative cycloaddition/annulation reactions. The unique photophysical properties of these metal complexes enable the formation of C C bonds with exceptional efficiency and selectivity. We dissect the mechanistic details of EnT and SET processes, illuminating the critical roles of light absorption, excited state generation, and substrate activation by the metal complexes. Subsequently, we explore the mechanisms, substrate scope, and synthetic transformations of dearomative cycloadditions involving hetero- and carbocyclic arenes (e.g., 2 + 2, 3 + 2, 4 + 2). The potential for discovering therapeutically relevant molecules through this approach will be addressed. We acknowledge the limitations and future directions for advancement. Finally, a miscellaneous section will highlight noteworthy research findings beyond the core focus, further emphasizing the captivating potential of dearomative photocycloadditions. [Display omitted] • Innovative Dearomatization Cycloaddition • Cutting-Edge Visible Light Catalysis • Pioneering Photocatalysis with Transition Metals • Energy /Electron Transfer Catalysis Unleashed • Broad Substrate Scope [ABSTRACT FROM AUTHOR]

A mechanochemical direct selenocyanation of arenes/heterocyclic arenes with electrophilic selenocyanating reagents to access (hetero)aryl selenocyanates has been developed. This protocol provided an efficient strategy to access various aromatic selenocyanates in yields up to 99 % under ball‐milling reaction conditions within 60 minutes. Gram‐scale reaction and further transformations of the product were conducted to demonstrate the synthetic utilities of this method. [ABSTRACT FROM AUTHOR]

Herein, Pd‐catalyzed CH acetoxylation reactions of arenes are developed using a pyrazolonaphthyridine ligand. In the presence of iodomesitylene diacetate as the oxidant, the electron‐deficient ligand facilitates the CH activation of the electron‐rich positions while preventing the formation of Pd black via bidentate binding. Although both acetic acid and hexafluoroisopropanol are employed for directing group‐assisted acetoxylation reactions, the latter proved to be more efficient for the nondirected reaction of arenes with the nitrogen ligand. [ABSTRACT FROM AUTHOR]

Helical fused anthracenes were elongated by fusing additional aromatic units at both ends to yield novel expanded helicenes. Compounds [5]HA2N and [7]HA consisting of 19 and 21 benzene rings, respectively, were synthesized by fourfold cycloisomerization of the corresponding terminal alkyne precursors. The helical structures were confirmed by X-ray crystallographic analysis, where the aromatic frameworks stacked effectively with the helical turn numbers exceeding two. The enantiomers of the two compounds were resolved by chiral HPLC. Whereas [5]HA2N readily underwent enantiomerization at room temperature at the barrier to enantiomerization of 91 kJ mol-1, the barrier was enhanced to 99 kJ mol-1 for the long analog [7]HA. The enantiomers of [7]HA exhibited strong responses in the circular dichroism (CD) and circularly polarized luminescence (CPL) spectra, as scaled by dissymmetry factors |gabs| = 0.034 and |glum| = 0.012. Theoretical calculations by the r2SCAN-3c method suggested stepwise mechanisms for the enantiomerization via helical inversion with acceptable barrier heights. The unexpectedly flexible nature of the aromatic frameworks of [5]HA2N and [7]HA was discussed on the basis of the proposed mechanism., (© 2024 Wiley‐VCH GmbH.)

Half-sandwich Ru(II)- and Os(II)-arene complexes have great potential for catalytic and biological applications. The possibility of fine-tuning their chemical reactivity by including modifications in the ligands around the metal adds to their many advantages. However, structural modifications at the η 6 -bound arene have had significant synthetic limitations, particularly in the design of Os(II)-tethered complexes. For the first time, we have employed a practical C(sp 3 )-C(sp 2 ) coupling to obtain 28 new Ru(II) and Os(II) η 6 -arene half-sandwich complexes with a wide variety of arene functionalities, including those that enable the formation of tether rings, such as quinoline, and coumarin. The introduction of novel functional groups at the arene in Ru(II)- and Os(II) half-sandwich complexes can broaden the synthetic scope of this type of organometallic complexes, and help to take full advantage of their structural diversity, for example, in intracellular catalysis., (© 2024 Wiley-VCH GmbH.)

Site-selective functionalization of simple arenes remains a paramount challenge due to the similarity of multiple C–H bonds in the same molecule with similar steric environment and electronic properties. Recently, the site-selective thianthrenation/phenoxathiination of arenes has become an attractive solution to reach this challenging goal and it has been applied in the late-stage functionalization of various bioactive molecules. This short review aims to summarize recent advances in the site-selective C–H functionalization of arenes via aryl thianthrenium salts, as well as mechanistic insights in the remarkable site-selectivity obtained in thianthrenation step. 1 Introduction 2 Site-Selective Thianthrenation of Arenes and Mechanistic Insight 3 Thianthrenation-Enabled Site-Selective Functionalization of Arenes 3.1 Thianthrenation-Enabled C(sp 2)–C Bond Formation Reaction 3.2 Thianthrenation-Enabled C(sp 2)–X Bond Formation Reaction 4 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

Four novel curved polycyclic aromatic hydrocarbons 3 a, 5, 8, 15 a have been synthesized and characterized, where molecules 3 a and 15 a bear [5]carbohelicene units. X‐ray single crystal analyses indicate that compound 3 a shows offset packing arrangements of (P5)‐ and (M5)‐isomers, and 15 a has a symmetrical plane and looks like a butterfly. In comparison, 8 exhibits a slightly curved structure, in which the significant convex‐to‐convex π‐overlap with the shortest distance of 3.42 Å occurs. In addition, the effect of annulation mode of twistarenes on the physical properties, self‐assembly behaviors, and switchable photoconductivity of the as‐prepared curved aromatic compounds were further examined in a comparative manner. [ABSTRACT FROM AUTHOR]

The current mainstream energy storage systems are in urgent need of performance improvements to meet novel application requirements. In pursuit of a higher energy density in Li-ion and Na-ion batteries, the conventional electrode materials have reached the upper limit of their theoretical specific capacities. Hence, facile methods of reducing irreversible lithium-ion/sodium-ion loss are developed to further boost the battery energy density. Herein, we review studies that use polycyclic aromatic hydrocarbons for wet chemical prelithiation and presodiation. The molecular structures of arenes and solvents used for solution-based prelithiation/presodiation have a substantial impact on the prelithiation/presodiation power and effectiveness. Multiple reports have already shown excellent initial Coulombic efficiency and streamlined processes by using this type of wet chemical prelithiation/presodiation strategy. This review article will cover how to select appropriate polycyclic aromatic hydrocarbon prelithiation/presodiation reagents for various materials/electrodes and provide possible directions and guidelines for future works. [ABSTRACT FROM AUTHOR]

Directly converting lignite into arenes as commodity chemicals and drop-in fuels is a highly desirable target for researchers. However, this is severely limited by the presence of stable inter unit C-O linkages in lignite. Herein, a highly active catalyst, Co-MoS 2 , has been designed and prepared to be used for the selective catalytic cleavage of inter unit C-O bridged bonds (BBs) in the conversion of Naomaohu (NMH), a lignite, to yield arenes. Both catalytic hydrogenation conversion (CHC) and thermal dissolution (a non-catalytic process, named NCHC) of NMH were conducted using n-hexane as the solvent. The soluble fractions from the first stage of NCHC (SF NCHC-1) and CHC (SF CHC-1), as well as the second stage of NCHC (SF NCHC-2) and CHC (SF CHC-2) were obtained using the same solvent. After the first-stage catalytic treatment, the relative contents of arenes and alkanes in SF CHC-1 increased by 16.7 % and 9.3 %, respectively, compared to those in SF NCHC-1 , and the relative content of oxygen-containing compounds (OCCs), such as alcohols, phenols, esters, ketones, acids, and furans, decreased by 13.2 %. For the second-stage conversion, the relative contents of arenes and alkanes in SF CHC-2 were 53.5 % and 15.5 % higher than those in SF NCHC-2 , and the relative contents of OCCs was only 6.6 % in SF CHC-2. The catalytic mechanisms of cleavage of C-O BBs and deoxygenation were proposed based on the CHC of model compounds and density functional theory (DFT) calculation. The adsorption of OCCs and the activation of released hydrogen radical (H·) by Co-MoS 2 , followed by H· addition to the carbon atom connected to oxygen in C-O BBs and oxygen-containing functional groups, are crucial for the cleavage of C-O BBs and formation of deoxygenated compounds, particularly arenes. • Co@MoS 2 selectively cleave C-O bridged bonds in lignite. • Co@MoS 2 is effective for hydrodeoxygenation and generation of arenes. • C ar -O cleavage mechanism was revealed by catalytic model compounds and DFT calculation. [ABSTRACT FROM AUTHOR]

High-efficiency production of xylene/trimethylbenzene from benzene/toluene with methanol is a potential way to promote the implementation on the coupled cycle development strategy of petrochemical and coal chemical industry and optimize the resource structure. At the same time, relying on the innovation of catalytic new materials, physical chemistry, intelligent capture technology, process engineering, and other principles and methods, p-xylene (PX) and trimethylbenzene (TMB) with higher added value were prepared by C6-8~arene methylation, which could elevate the level of methylation field and improve the competitiveness of the industry. This paper focuses on the one-step methylation reaction of benzene with methanol or toluene with methanol to obtain high-purity p-xylene (BM-PX/TM-PX), and the one-step methylation reaction of xylene with methanol to obtain mesitylene (XM-TMB). The methylation reaction mechanism and the preparation strategy of a high-performance catalyst were reviewed. The high selectivity of PX obtained by precisely controlling the pore size and acid site distribution of zeolites was emphasized. Meanwhile, the current research progress of TMB, the kinetic/thermodynamics of the BM-PX/TM-PX, and XM-TMB methylation reaction were described. Based on a literature research and the conclusion of our research group, the mechanism of methylation reaction process was expounded. Finally, the new research direction of catalysts used and reaction process in methylation reaction were prospected in order to guide the rapid development of this field. [ABSTRACT FROM AUTHOR]

Sulfoximines are an interesting class of compounds, which exhibit Brønsted and Lewis basicity, nucleophilicity, C−H acidity, N−H acidity, hydrogen‐bond acceptor capability and chirality. Sulfoximines have received renewed interest in recent times, since incorporation of a sulfoximine group can provide drug candidates with favorable properties. The synthesis and N−H, α‐C−H and o‐C−H functionalization of sulfoximines are currently topics of considerable interest. This Minireview describes the sulfoximine‐directed arene ortho‐lithiation and the synthesis of ortho‐substituted S‐aryl sulfoximines. Comparison between the sulfoximine and sulfone group shows that both are equally potent directors in arene ortho‐lithiation. Double ortho‐lithiation of S‐phenyl sulfoximines affords o,o'‐dilithiosulfoximines, which undergo a stereoretentive rearrangement to o‐sulfinylanilines. S‐Phenyl sulfoximines, carrying a α‐hydrogen atom, are amendable to a selective ortho‐lithiation to give o‐lithiosulfoximines, which suffer transmetalation to the α‐lithiosulfoximines at ambient temperatures. Double lithiation of S‐phenyl N−H sulfoximines gives access to o,N‐dilithiosulfoximines, the reaction of which with biselectrophiles yields bicyclic sulfoximines. [ABSTRACT FROM AUTHOR]

The reactivity of the reduced anthracene complex of scandium [Li(thf)3][Sc{N(tBu)Xy}2(anth)] (2‐anth‐Li) (Xy=3,5‐Me2C6H3; anth=C14H102−, thf=tetrahydrofuran) toward Brønsted acid [NEt3H][BPh4] and azobenzene is reported. While a stepwise protonation of 2‐anth‐Li with two equivalents of [NEt3H][BPh4] afforded the scandium cation [Sc{N(tBu)Xy}2(thf)2][BPh4] (3), reduction of azobenzene gave a thermolabile, anionic scandium reduced azobenzene complex [Li(thf)][Sc{N(tBu)Xy}2(η2‐PhNNPh)] (4), which slowly lost one of the anilide ligands to form the neutral scandium azobenzene complex dimer [Sc{N(tBu)Xy}(μ‐η2:η2‐Ph2N2)]2 (5). Exposure of 3 to CO2 produced the scandium carbamate complex [Sc{κ2‐O2CN(tBu)(Xy)}2][BPh4] (6) as a result of CO2 insertion into the Sc−N bonds. In an attempt to prepare scandium hydrides, the reaction of 3 with the hydride sources LiAlH4 and Na[BEt3H] led to the terminal aluminum hydride [AlH{N(tBu)Xy}2(thf)] (7) and the scandium n‐butoxide [Sc{N(tBu)(Xy)}2(μ‐OnBu)] (8) after Sc/Al transmetalation and nucleophilic ring‐opening of THF, respectively. All reported compounds isolated in moderate to good yields were fully characterized. [ABSTRACT FROM AUTHOR]

Aryldiphenylarsines, diarylphenylarsines, and triarylarsines were synthesized by practical methods to utilize the heavy atom effect for phosphorescence. 1‐Naphthyl, 2‐naphthyl, 9‐phenanthryl, and 1‐pyrenyl groups were introduced in the present work. The obtained arene‐substituted arsines showed phosphorescence in solutions at 77 K. On the other hand, 1‐pyrenyl‐substituted arsines showed only fluorescence in the solid states at 77 K, whereas the others exhibited phosphorescence. In addition, oxidation of the arsenic atom promoted fluorescence instead of phosphorescence. X‐ray crystallography and computational calculations were conducted to understand the luminescence behaviors of the arene‐substituted arsines. [ABSTRACT FROM AUTHOR]

Here reports a highly regio‐ and diastereoselective haliranium ion‐induced intermolecular Friedel‐Crafts reaction of α,β‐unsaturated carbonyl compounds in HFIP. The operationally simple and mild method affords the synthetically useful β,β‐diarylated α‐halo carbonyl compounds in good yields after a very short reaction time. As an application, a few examples of β,β‐diarylated olefins are prepared in excellent yields. Based on the experimental results and a qualitative study of 1D‐NMR‐experiments, a plausible reaction mechanism is proposed. [ABSTRACT FROM AUTHOR]

Kürzlich wurden Palladium‐Katalysatoren entdeckt, die eine nicht‐dirigierte C‐H‐Aktivierung von Arenen ermöglichen, ohne dass ein Überschuss des Aren‐Substrats erforderlich ist, sodass Methoden entwickelt werden konnten, die die Modifikation fortgeschrittener Syntheseintermediate ermöglichen. Der Schlüssel zum Erfolg war die Verwendung zweier komplementärer Liganden, einer N‐Acylaminosäure und eines N‐Heterozyklus. Detaillierte experimentelle und computergestützte mechanistische Studien zur mittels zweier kooperativer Liganden ermöglichten C‐H‐Aktivierung von Arenen haben uns zur Identifizierung der katalytisch aktiven Spezies und eines Übergangszustandsmodells geführt, das die außergewöhnliche Aktivität und Selektivität dieser Katalysatoren erklärt. Diese Erkenntnisse dürften für die weitere Methodenentwicklung unter Verwendung dieser leistungsstarken Katalysatorklasse von großem Nutzen sein. [ABSTRACT FROM AUTHOR]

The prevalence of sulfones in natural products, pharmaceutically active molecules and functional materials draw immense attention for their synthesis. Here, we report a palladium‐catalyzed protocol for synthesizing diaryl sulfones from the arenes through C−H activation. N‐methoxy arenesulfonamide was exploited as a potential sulfonyl donor by the cleavage of S−N bond through a radical pathway. The present methodology has several advantages: a simple, readily available catalytic system; the use of a stable sulfonyl donor; a relatively moderate excess of arene coupling partner for an undirected C−H activation process, along with the tolerances of aryl bromides and iodides, which in turn permits further cross‐coupling reactions to afford cross‐coupled sulfones. [ABSTRACT FROM AUTHOR]

The current mainstream energy storage systems are in urgent need of performance improvements to meet novel application requirements. In pursuit of a higher energy density in Li-ion and Na-ion batteries, the conventional electrode materials have reached the upper limit of their theoretical specific capacities. Hence, facile methods of reducing irreversible lithium-ion/sodium-ion loss are developed to further boost the battery energy density. Herein, we review studies that use polycyclic aromatic hydrocarbons for wet chemical prelithiation and presodiation. The molecular structures of arenes and solvents used for solution-based prelithiation/presodiation have a substantial impact on the prelithiation/presodiation power and effectiveness. Multiple reports have already shown excellent initial Coulombic efficiency and streamlined processes by using this type of wet chemical prelithiation/presodiation strategy. This review article will cover how to select appropriate polycyclic aromatic hydrocarbon prelithiation/presodiation reagents for various materials/electrodes and provide possible directions and guidelines for future works.

Abstract Construction of crystalline homo/heteroaggregation at micro/nanometer level from organic π‐conjugated systems is of great importance because the controllable morphologies (i.e., size, shape, and dimension) could provide diverse optoelectronic properties for different applications in the electrooptical devices. In this review, we summarize our recent progress in the self‐assembly of micro/nanostructures of organic π‐conjugated molecules via the heteroaggregation and homoaggregation strategies. We also discuss various factors (i.e., temperature, solvents, and surfactants) that affect the aggregation process through a surfactant‐assisted reprecipitation method. Moreover, their physical properties and possible applications in electronics and biofields are illustrated.

Pillar[n]arene is one of the most favorited supramolecular materials that possess a special chiral structure. The major property of pillar-structured materials is their high cavity, and this structure is able to dominate the higher cavity values due to the big number of n (5,6,7) as hydroquinone units. Thanks to this significant property, pillar[n]arenes can be preferred to use in a wide application area. The chemical sensor application of pillar[n]arenes is one of the most applicable one, because they are more prominent than other macrocyclic skeletons (calixarene, crown ether, etc.) in the related area. Although the studies on chemical sensor application by using pillar[n]arenes as sensing elements have been performed so far, the thin film of these macrocyclic architectures, have been very limited in the available literature. Therefore, the recent developments of pillar[n]arene-based thin films and their chemical sensor applications are investigated and discussed in this review article. [ABSTRACT FROM AUTHOR]

The heterometallic complex (L1)Ru(κ2-O2CC5H4)Mn(CO)3(O2CC5H4)Mn(CO)3) (I) (L1 is the pivalate ligand) is synthesized by the reaction of the ruthenium(II) complex (L1)Ru(κ2-O2CCMe3)(O2CCMe3) with cymantrenylcarboxylic acid (HO2CC5H4)Mn(CO)3. The consecutive reactions of nickel acetate with cymantrenenecarboxylic acid and diimine 1,4-di-tert-butyl-1,4-diazabutadiene-1,3 affords the complex (L2)Ni(κ2-O2CC5H4Mn(CO)3)2 (II) (L2 = tBu–N=CH–CH=N–tBu). Complexes I and II are identified by the elemental and X-ray diffraction analyses data (СIF files CCDC nos. 2001354 (I) and 2001355 (II)). [ABSTRACT FROM AUTHOR]

The generation of bromine by oxidation of bromide anions at the anode and reduction of molecular oxygen at the cathode to hydrogen peroxide resulted in the overall formation of two molecules of Br2 (=four electron oxidation) by passing just two electrons through the solution. The bromine was used for the bromination of alkenes and thereby a linear paired electrolysis was attained which resulted in current efficencies of up to 200 %. Also, the diiodination of cyclohexene as well as the electrophilic aromatic bromination of an electron‐rich arene were realised both in 168 % current efficiencies. [ABSTRACT FROM AUTHOR]

Herein we report visible‐light‐induced intramolecular double dearomative cycloaddition of arenes. Compared with the well‐known photodimerization of arenes under ultraviolet irradiation, the current reactions are carried out under mild conditions and feature wide substrate scope. A large array of structurally‐diverse polycyclic indoline derivatives is afforded in high yields (up to 98 %) with exclusive diastereoselectivity (>20:1 dr) via dearomative [4+2] or [2+2] pathway. [ABSTRACT FROM AUTHOR]

We have, like many others, contributed to the development and to the popularity of arene ruthenium assemblies. From early on, our research was driven by applications, mainly biological (therapeutic, drug delivery, DNA interactions, photodynamic therapy, imaging). For nearly 15 years, we have focused on the use of arene ruthenium building block as a tool to construct added‐value objects. In this account, we want to give the basic reasons behind our choice, and uncover our most successful examples, with an emphasis on the foreseen applications. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: Site‐selective borylation of simple arenes was realized in one pot via an electrophilic thianthrenation/Pd‐catalyzed borylation sequence. The key to achieve this operatically simple process is the use of Pd catalysis, which could tolerate the solvent and acidic conditions used in the thianthrenation step. This protocol features mild conditions, broad functional group tolerance, and simple manipulations, and is suitable for late‐stage functionalization of a wide range of pharmaceuticals and complex bioactive molecules. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: Site‐selective borylation of simple arenes was realized in one pot via an electrophilic thianthrenation/Pd‐catalyzed borylation sequence. The key to achieve this operatically simple process is the use of Pd catalysis, which could tolerate the solvent and acidic conditions used in the thianthrenation step. This protocol features mild conditions, broad functional group tolerance, and simple manipulations, and is suitable for late‐stage functionalization of a wide range of pharmaceuticals and complex bioactive molecules. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: A silver‐mediated oxidative trifluoromethylation of easily accessible α‐trifluoromethyl alcohols with TMSCF3 was developed to access novel CF3(OCF3)CH‐containing compounds. Deprotonation of CF3(OCF3)CH‐substituted arenes afforded synthetically useful CF3O‐substituted gem‐difluoroalkenes. Furthermore, evaluation of the lipophilicities (log P) indicated that CH(OCF3)CF3 is more lipophilic than the common fluorinated motifs such as CF3, OCF3, and SCF3, thus rendering the CH(OCF3)CF3 motif appealing in drug discovery. [ABSTRACT FROM AUTHOR]

Nowadays in cancer treatment, both metal complexes and organic molecules are being widely used. Current years have seen a surge of interest in the application of organometallic compounds to treat cancer and other diseases. Undeniably, the unique properties of organometallic compounds, intermediate between those of classical inorganic and organic materials, provide new opportunities in the field of medicinal chemistry. Since the discovery of cisplatin, many transition metal complexes have been synthesized and assayed for anticancer activity. In recent years, ruthenium‐based Schiff base complexes have emerged as promising antitumor and antimetastatic agents with potential uses in treatment of platinum‐resistant tumors or as alternatives to platinum‐based chemotherapy. Advantages of utilizing ruthenium complexes in drug development include reliable methods of synthesizing stable complexes; the ability to tune ligand affinities, electron transfer and substitution rates, and reduction potentials; and an increasing knowledge of the biological effects of such complexes. This great expansion of ruthenium‐based Schiff base complexes is mainly due to the unique ability of the ruthenium core to permit multiple oxidation states, hence versatile electron‐transfer pathways, and because of the ease of preparation with versatile and variable‐denticity Schiff base ligands. This review aims to bring the reader up to date with the more recent Ru(II)/(III)‐based Schiff base complexes that have been synthesized and investigated for their cytotoxicity. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: A silver‐mediated oxidative trifluoromethylation of easily accessible α‐trifluoromethyl alcohols with TMSCF3 was developed to access novel CF3(OCF3)CH‐containing compounds. Deprotonation of CF3(OCF3)CH‐substituted arenes afforded synthetically useful CF3O‐substituted gem‐difluoroalkenes. Furthermore, evaluation of the lipophilicities (log P) indicated that CH(OCF3)CF3 is more lipophilic than the common fluorinated motifs such as CF3, OCF3, and SCF3, thus rendering the CH(OCF3)CF3 motif appealing in drug discovery. [ABSTRACT FROM AUTHOR]

Expanding the toolbox of C−H functionalization reactions applicable to the late‐stage modification of complex molecules is of interest in medicinal chemistry, wherein the preparation of structural variants of known pharmacophores is a key strategy for drug development. One manifold for the functionalization of aromatic molecules utilizes diazo compounds and a transition‐metal catalyst to generate a metallocarbene species, which is capable of direct insertion into an aromatic C−H bond. However, these high‐energy intermediates can often require directing groups or a large excess of substrate to achieve efficient and selective reactivity. Herein, we report that arene cation radicals generated by organic photoredox catalysis engage in formal C−H functionalization reactions with diazoacetate derivatives, furnishing sp2–sp3 coupled products with moderate‐to‐good regioselectivity. In contrast to previous methods utilizing metallocarbene intermediates, this transformation does not proceed via a carbene intermediate, nor does it require the presence of a transition‐metal catalyst. [ABSTRACT FROM AUTHOR]

A highly regioselective Ni‐catalyzed electrochemical reductive relay cross‐coupling between an aryl halide and an alkyl halide has been developed in an undivided cell. Various functional groups are tolerated under these mild reaction conditions, which provides an alternative approach for the synthesis of 1,1‐diarylalkanes. [ABSTRACT FROM AUTHOR]

The partial fluorination of polycyclic aromatic hydrocarbons often produces a layered crystal packing, where fluorinated aromatic surfaces are stacked over nonfluorinated aromatic surfaces. Herein, we report the synthesis and crystal packing of partially fluorinated [4]helicenes with steric congestion resulting from H and F atoms in the fjord region. F6‐[4]Helicene forms head‐to‐tail columnar stacks consisting of an alternate arrangement of perfluorinated and nonfluorinated naphthalene moieties. With decreasing fluorine content, aromatic stacking switched from arene−fluoroarene (ArH−ArF) hetero‐stacking to ArH−ArH/ArF−ArF homo‐stacking with the help of intermolecular C−H⋅⋅⋅F contacts in the fjord region. As a result, head‐to‐head columnar stacks appear. Therefore, the conventional ArH−ArF stacking motif is not always applicable to Fn‐[4]helicenes with twisted π‐surfaces. [ABSTRACT FROM AUTHOR]

The aminoazanium of DABCO (H2N‐DABCO) has been developed as a general and practical amination reagent for the direct amination of alkyl and aryl pinacol boronates. This compound is stable and practical for use as a reagent. Various primary, secondary. and tertiary alkyl−Bpin and aryl−Bpin substrates were aminated to give the corresponding amine derivatives. The amination is stereospecific. The anti‐Markovnikov hydroamination of olefins was easily achieved by catalytic hydroboration with HBpin and in subsequent situ amination using H2N‐DABCO. Moreover, the combination of 1,2‐diboration of olefins, using B2pin2, with this amination process achieved the unprecedented 1,2‐diamination of olefins. The amination protocol was also successfully extended to aryl pinacol boronates. [ABSTRACT FROM AUTHOR]

Oxidative C−H/C−H coupling of arenes were carried out on palladium nitrosyl carboxylates Pd3(NO)2(CX3CO2)4(ArH)2 (I: X=Cl, Ar=Ph; II: X=F, Ar=Tol) under relatively mild conditions (5 bars of O2, 110 °C, 24 h). Over trifluoroacetate complex II, we obtained higher yields in both homocoupling of benzene and heterocoupling of benzene and other arenes. The catalytic system showed high selectivity over 90 % for all the studied substrates. The DFT calculations on the activation of arene through the proton transfer showed that the activation energies for all possible intramolecular pathways are much higher than those for the proton transfer to free carboxylate ions, indicating that the presence of external base is required to increase the performance of the considered catalytic system. In the catalytic tests it was found that the preferable external bases are ions of strong carboxylic acids, while acetate provides almost negligible improvement and pyridine suppresses the reaction most likely due to binding to active sites on palladium. [ABSTRACT FROM AUTHOR]

Although the application of arene-osmium(II) complexes in homogeneous catalysis has been much less studied than that of their ruthenium analogues, different works have shown that, in some instances, a comparable or even superior effectiveness can be achieved with this particular class of compounds. This review article focuses on the catalytic applications of arene-osmium(II) complexes. Among others, transfer hydrogenation, hydrogenation, oxidation, and nitrile hydration reactions, as well as different C-C bond forming processes, are comprehensively discussed.

A convenient and efficient domino aryne process was developed under transition‐metal‐free conditions to generate a range of tetra‐ and pentacyclic ring systems. This transformation was realized via a 1,2‐benzdiyne through a nucleophilic and Diels–Alder reaction cascade using styrene as the diene moiety. Three new chemical bonds, namely one C−N and two C−C bonds, and two benzofused rings could be constructed concomitantly, which was made possible by distinct chemoselective control at both the 1,2‐aryne and 2,3‐aryne stages. Moreover, in‐depth studies were carried out on the domino aryne precursors and controlling the diastereoselectivity. [ABSTRACT FROM AUTHOR]

Atroposelective arene formation is an efficient method to build axially chiral molecules with multi‐substituted arenes. Reported here is an organocatalyzed atroposelective arene formation reaction by an N‐heterocyclic carbene (NHC) catalyzed formal [4+2] cycloaddition of conjugated dienals and α‐aryl ketones. This study expands the synthetic potential of NHC organocatalysis and provides a competitive pathway for the synthesis of axially chiral ligands, catalysts, and other functional molecules. [ABSTRACT FROM AUTHOR]

The Pd‐catalyzed coupling of aryl (pseudo)halides and amines is one of the most powerful approaches for the formation of C(sp2)−N bonds. The pioneering reports from Migita and subsequently Buchwald and Hartwig on the coupling of aminostannanes and aryl bromides rapidly evolved into general and practical tin‐free protocols with broad substrate scope, which led to the establishment of what is now known as the Buchwald–Hartwig amination. This Minireview summarizes the evolution of this cross‐coupling reaction over the course of the past 25 years and illustrates some of the most recent applications of this well‐established methodology. [ABSTRACT FROM AUTHOR]

A new strategy is demonstrated for the synthesis of warped, negatively curved, all‐sp2‐carbon π‐scaffolds. Multifold C−C coupling reactions are used to transform a polyaromatic borinic acid into a saddle‐shaped polyaromatic hydrocarbon (2) bearing two heptagonal rings. Notably, this Schwarzite substructure is synthesized in only two steps from an unfunctionalized alkene. A highly warped structure of 2 was revealed by X‐ray crystallographic studies and pronounced flexibility of this π‐scaffold was ascertained by experimental and computational studies. Compound 2 exhibits excellent solubility, visible range absorption and fluorescence, and readily undergoes two reversible one‐electron oxidations at mild potentials. [ABSTRACT FROM AUTHOR]

A palladium‐catalyzed dearomative syn‐1,4‐oxyamination protocol using non‐activated arenes has been developed. This one‐pot procedure utilizes arenophile chemistry, and the corresponding para‐cycloadducts are treated with oxygen nucleophiles via formal allylic substitution, providing direct access to syn‐1,4‐oxyaminated products. The reaction conditions permit a range of arenes, as well as different O‐nucleophiles, such as oximes and benzyl alcohols. Moreover, this process was established in an asymmetric fashion, delivering products with high enantioselectivity. The dearomatized products are amenable to a multitude of further derivatizations ranging from olefin chemistry to C−H activation, giving rise to a diverse set of new functionalities. Overall, this dearomative functionalization offers rapid and controlled formation of molecular complexity, enabling straightforward access to functionalized small molecules from simple and readily available arenes. [ABSTRACT FROM AUTHOR]