A Strategy for Selective Catalytic B–H Functionalization of o-Carboranes

Accounts of Chemical Research, Journal Year: 2021, Volume and Issue: 54(21), P. 4065 - 4079

Published: Oct. 24, 2021

ConspectusCarboranes are a class of polyhedral carbon-boron molecular clusters featuring three-dimensional aromaticity, which often considered as 3D analogues benzene. Their unique structural and electronic properties make them invaluable building blocks for applications ranging from functional materials to versatile ligands pharmaceuticals. Thus, selective functionalization carboranes has received tremendous research interest. In earlier days, the vast majority works in this area were focused on cage carbon via facile deprotonation CH, followed by reaction with electrophiles. On contrary, B-H activation is very challenging since 10 bonds o-carborane similar, how achieve desired transformation at specific boron vertex long-standing issue.As more electronegative than boron, property results different charges cage, follow order B(3,6)-H ≪ B(4,5,7,11)-H < B(8,10)-H B(9,12)-H. We thought that difference may trigger favorite interaction proper transition metal complex bond carborane, could be utilized solve selectivity issue. Accordingly, our strategy described follows: (1) electron-rich catalysts good most electron-deficient (connected both C-H vertices); (2) relatively B(8,9,10,12)-H (with no bonding either (3) directing-group-assisted catalysis appropriate only one vertex), whose lie middle range bonds. This been successfully applied laboratory other groups development series synthetic routes catalytic carborane resulting synthesis large number cage-boron-functionalized derivatives regioselective fashion. Subsequently, significant progress emerging made.In 2013 we reported tetrafluorination o-carboranes using an Pd(II) salt, [Pd(MeCN)4][BF4], catalyst. 2014 disclosed first example carboxy-directed alkenylation B(4) promoted Ir(III) 2017 presented Ir(I)-catalyzed diborylation also uncovered Pd-catalyzed asymmetric chiral-at-cage 2018. These proof-of-principle studies have greatly stimulated activities enabled catalysts. so far developed toolbox methods B-olefination, -arylation, -alkenylation, -alkynylation, -oxygenation, -sulfenylation, -borylation, -halogenation, -amination. recently expanded base catalysis. As field progresses, expect will invented, detailed Account promote these efforts.

Language: Английский

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The Rise of Boron-Containing Compounds: Advancements in Synthesis, Medicinal Chemistry, and Emerging Pharmacology

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(5), P. 2441 - 2511

Published: Feb. 21, 2024

Boron-containing compounds (BCC) have emerged as important pharmacophores. To date, five BCC drugs (including boronic acids and boroles) been approved by the FDA for treatment of cancer, infections, atopic dermatitis, while some natural are included in dietary supplements. Boron's Lewis acidity facilitates a mechanism action via formation reversible covalent bonds within active site target proteins. Boron has also employed development fluorophores, such BODIPY imaging, carboranes that potential neutron capture therapy agents well novel diagnostics therapy. The utility synthetic become multifaceted, breadth their applications continues to expand. This review covers many uses targets boron medicinal chemistry.

Language: Английский

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Regulation of stem cell fate and function by using bioactive materials with nanoarchitectonics for regenerative medicine

Science and Technology of Advanced Materials, Journal Year: 2022, Volume and Issue: 23(1), P. 393 - 412

Published: June 6, 2022

Nanoarchitectonics has emerged as a post-nanotechnology concept. As one of the applications nanoarchitectonics, this review paper discusses control stem cell fate and function an important issue. For hybrid nanoarchitectonics involving living cells, it is crucial to understand how biomaterials their nanoarchitected structures regulate behaviours fates cells. In review, for regulation are firstly discussed. Besides multipotent differentiation, immunomodulation biological mesenchymal cells (MSCs). MSCs can modulate immune treat multiple immune- inflammation-mediated diseases. The following sections summarize recent advances immunomodulatory functions by biophysical signals. third part, we discussed direct self-organization pluripotent organoid. Bioactive materials constructed which mimic cues in vivo microenvironment such elasticity, viscoelasticity, biodegradation, fluidity, topography, geometry, etc. Stem interpret these different cytoskeletal forces. forces lead substantial transcription protein expression, affect function. Regulations could not be utilized only tissue repair regenerative medicine but also potentially production advanced systems. Materials with integration related substances would have high impacts science technology materials.

Language: Английский

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Direct B–H Functionalization of Icosahedral Carboranes via Hydrogen Atom Transfer

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(13), P. 7638 - 7647

Published: March 22, 2023

The efficient and selective functionalization of icosahedral carboranes (C2B10H12) at the boron vertexes is a long-standing challenge owing to presence 10 inert B-H bonds in similar chemical environment. Herein, we report new reaction paradigm for direct via homolysis enabled by nitrogen-centered radical-mediated hydrogen atom transfer (HAT) strategy. Both HAT process carborane bond resulting boron-centered carboranyl radical intermediate have been confirmed experimentally. occurs most electron-rich vertex with lowest dissociation energy (BDE). Using this strategy, diverse derivatization, including thiolation, selenation, alkynylation, alkenylation, cyanation, halogenation, achieved satisfactory yields under photoinitiated condition metal-free redox-neutral fashion. Moreover, synthetic utility current protocol was also demonstrated both scale-up construction carborane-based functional molecules. Therefore, methodology opens pathway functionalization, which distinct from heterolytic mechanism traditional strategies.

Language: Английский

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B(9)-OH-o-Carboranes: Synthesis, Mechanism, and Property Exploration

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(13), P. 7331 - 7342

Published: March 24, 2023

Herein, we present a chemically robust and efficient synthesis route for B(9)-OH-o-carboranes by the oxidation of o-carboranes with commercially available 68% HNO3 under assistance trifluoromethanesulfonic acid (HOTf) hexafluoroisopropanol (HFIP). The reaction is highly wide scope carboranes, selectivity B(9)/B(8) up to 98:2. success this transformation relies on strong electrophilicity oxidizability HNO3, promoted through hydrogen bonds Brønsted HOTf solvent HFIP. Mechanism studies reveal that o-carborane involves an initial electrophilic attack atom at most electronegative B(9) o-carborane. In transformation, B-H bond nucleophilic site, which different from substitution reaction, where boron site. Therefore, oxidation-reduction mild conditions in N(V) → N(III) H(-I) H(I). derivatization 9-OH-o-carborane was further examined, carboranyl group successfully introduced amino acid, polyethylene glycol, biotin, deoxyuridine, saccharide. Undoubtedly, approach provides selective way rapid incorporation carborane moieties into small molecules application neutron capture therapy, requires targeted delivery boron-rich groups.

Language: Английский

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Chemistry of three-dimensional icosahedral boron clusters anions: closo-dodecaborate (2-) [B12H12]2- and carba-closo-dodecaborate(-) [CB11H12]-

Coordination Chemistry Reviews, Journal Year: 2024, Volume and Issue: 516, P. 215974 - 215974

Published: June 8, 2024

Language: Английский

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Ir-Catalyzed Selective B(3)-H Amination of o-Carboranes with NH₃

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(11), P. 4148 - 4153

Published: March 15, 2021

Ammonia gas, NH3, is a cheap and widely used industrial feedstock, which has received tremendous research interests in its functionalization. This work reports breakthrough catalytic selective cage B(3)-H amination of o-carboranes with NH3 via Ir-catalyzed B-H/N-H dehydrocoupling, offering convenient efficient access to series 3-NH2-o-carborane derivatives moderate high isolated yields broad substrate scope. The employment readily available gas as the aminating reagent H2 sole byproduct endows protocol economy, practicability, environmental friendliness. A plausible reaction mechanism proposed on basis control experiments.

Language: Английский

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Ir-catalyzed enantioselective B−H alkenylation for asymmetric synthesis of chiral-at-cage o‑carboranes

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Dec. 8, 2021

Abstract The asymmetric synthesis of chiral-at-cage o -carboranes, whose chirality is associated with the substitution patterns on polyhedron, great interest as icosahedral carboranes have wide applications in medicinal and materials chemistry. Herein we report an intermolecular Ir-catalyzed enantioselective B−H alkenylation for efficient facile -carboranes new skeletons under mild reaction conditions. Generally very good to excellent yields up 99% ee can be achieved this alkenylation. enantiocontrol model proposed based Density Functional Theory calculations which use chiral phosphoramidite ligand essential such -carborane

Language: Английский

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Electrochemical Cage Activation of Carboranes

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(20)

Published: Feb. 11, 2022

Abstract Carboranes are boron–carbon molecular clusters that possess unique properties, such as their icosahedron geometry, high boron content, and delocalized three‐dimensional aromaticity. These features render carboranes valuable building blocks for applications in supramolecular design, nanomaterials, optoelectronics, organometallic coordination chemistry, neutron capture therapy (BNCT) agents. Despite tremendous progress this field, stoichiometric chemical redox reagents largely required the oxidative activation of carborane cages. In context, electrosyntheses represent an alternative strategy more sustainable syntheses. It is only recent few years considerable has been made electrochemical cage functionalization carboranes, which summarized Minireview. We anticipate electrocatalysis will serve increasingly powerful stimulus within current renaissance electrochemistry.

Language: Английский

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Mechano‐Nanoarchitectonics: Design and Function

Small Methods, Journal Year: 2022, Volume and Issue: 6(5)

Published: March 29, 2022

Abstract Mechanical stimuli have rather ambiguous and less‐specific features among various physical stimuli, but most materials exhibit a certain level of responses upon mechanical inputs. Unexplored sciences remain in responding systems as one the frontiers science. Nanoarchitectonics approaches for mechanically are discussed mechano‐nanoarchitectonics this review article. Recent on molecular with response capabilities first exemplified two viewpoints: i) control supramolecular assemblies ii) evaluation atom/molecular structures. In following sections, special attentions interfacial environments emphasized. The section entitled iii) Control Molecular System at Dynamic Interface describes coupling macroscopic forces molecular‐level phenomena. Delicate can be applied to functional molecules embedded air–water interface where operation machines tuning receptors actions discussed. Finally, important role media further extended living cells described iv) Biosystems. Pioneering cell fate regulations liquid–liquid interfaces addition well‐known mechanobiology.

Language: Английский

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