Controlled functionalization ofo-carboraneviatransition metal catalyzed B–H activation

Chemical Society Reviews, Journal Year: 2019, Volume and Issue: 48(13), P. 3660 - 3673

Published: Jan. 1, 2019

This review summarizes recent advances in transition metal catalyzed vertex-specific BH functionalization ofo-carborane for controlled synthesis of its derivatives.

Language: Английский

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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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Carboranes as unique pharmacophores in antitumor medicinal chemistry

Molecular Therapy — Oncolytics, Journal Year: 2022, Volume and Issue: 24, P. 400 - 416

Published: Jan. 10, 2022

Carborane is a carbon-boron molecular cluster that can be viewed as 3D analog of benzene. It features special physical and chemical properties, thus has the potential to serve new type pharmacophore for drug design discovery. Based on relative positions two cage carbons, icosahedral closo-carboranes classified into three isomers, ortho-carborane (o-carborane, 1,2-C2B10H12), meta-carborane (m-carborane, 1,7-C2B10H12), para-carborane (p-carborane, 1,12-C2B10H12), all them deboronated generate their nido- forms. Cage compound carborane its derivatives have been demonstrated useful entities in antitumor medicinal chemistry. The applications carboranes field research mainly include boron neutron capture therapy (BNCT), BNCT/photodynamic dual sensitizers, anticancer ligands. This review summarizes progress achieved up October 2021, with particular emphasis signaling transduction pathways, structures, mechanistic considerations using carboranes.

Language: Английский

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Metal-catalyzed cross-coupling chemistry with polyhedral boranes

Chemical Communications, Journal Year: 2018, Volume and Issue: 55(4), P. 430 - 442

Published: Nov. 28, 2018

Over the past several decades, metal-catalyzed cross-coupling has emerged as a powerful strategy to functionalize polyhedral borane clusters.

Language: Английский

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Palladium-Catalyzed Selective Five-Fold Cascade Arylation of the 12-Vertex Monocarborane Anion by B–H Activation

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(42), P. 13798 - 13807

Published: Sept. 19, 2018

A series of cage penta-arylated carboranes have been synthesized by palladium-catalyzed intermolecular coupling the C-carboxylic acid monocarba- closo-dodecaborate anion [CB11H12]- with iodoarenes direct B-H bond functionalization. These transformations set a record in terms one-pot directing group-mediated activation inert bonds single molecule. The methodology is characterized high yields, good functional group tolerance, and complete regioselectivity. COOH can be easily removed during or after reaction. mechanistic pathways were probed using density theory calculations. Pd(II)-Pd(IV)-Pd(II) catalytic cycle proposed, which initial followed preferred adjacent boron vertex, continuation this selectivity results continuous walking process palladium center. opens new avenue toward building blocks 5-fold symmetry.

Language: Английский

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Recent Advances in Transition Metal-Catalyzed Selective B-H Functionalization ofo-Carboranes

Bulletin of the Chemical Society of Japan, Journal Year: 2020, Volume and Issue: 94(3), P. 879 - 899

Published: Dec. 18, 2020

Abstract Carboranes are a class of carbon-boron molecular clusters, possessing extraordinary characteristics including three-dimensional aromaticity conjugated by σ-bonds, icosahedral geometry and inherent robustness. They finding growing applications as valuable building blocks in boron neutron capture therapy agents, pharmacophores, nanomaterials, optoelectronic, organometallic/coordination chemistry more. Therefore, the effective controlled functionalization carboranes has attracted enormous research interests, particularly regio- enantio-selective cage BH derivatization among ten chemically similar vertices o-carboranes. Only recent few years, significant progress been made transition metal catalyzed vertex-specific functionalization. This review summarizes advances this realm.

Language: Английский

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Supramolecular Architectures Bearing Half-Sandwich Iridium- or Rhodium-Based Carboranes: Design, Synthesis, and Applications

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(36), P. 19440 - 19457

Published: Aug. 29, 2023

The utilization of carboranes in supramolecular chemistry has attracted considerable attention. unique spatial configuration and weak interaction forces can help to explore the properties complexes, particularly via host–guest chemistry. Additionally, certain difficulties encountered carborane development─such as controlled B–H bond activation─can be overcome by judiciously selecting metal centers their adjacent ligands. However, few studies are being conducted this nascent research area. With advances field, novel carborane-based complexes will likely prepared, structurally characterized, intrinsically investigated. To expedite these efforts, we present major findings from recent studies, including π–π interactions, associations, steric effects, which have been leveraged implement a regioselective process for activating B(2,9)–, B(2,8)–, B(2,7)–H bonds para-carboranes B(4,7)–H ortho-carboranes. Future should clarify interactions potential enhancing utility complexes. Although exhibit several (such dihydrogen-bond [Bδ+–Hδ−···Hδ+–Cδ−], Bδ+–Hδ−···M+, Bδ+–Hδ−···π interactions), manner they utilized remains unclear. Supramolecular those based on chemistry, platform demonstrating applications interactions. Owing importance alkane separation, related recognition separation isomers primarily summarized. Advances certainly lead more possibilities

Language: Английский

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Enantioselective Synthesis of Chiral-at-Cage o-Carboranes via Pd-Catalyzed Asymmetric B–H Substitution

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(13), P. 4508 - 4511

Published: March 26, 2018

Carborane cage chirality is an outstanding issue of great interest as the icosahedral carboranes have wide applications in medicinal and materials chemistry. The synthesis optically active carborane derivatives, whose associated with substitution patterns on polyhedron, will open new avenues to We report herein efficient method achieve chiral-at-cage arylation o-carboranes high regio- enantioselectivities by a strategy palladium-catalyzed asymmetric intramolecular B-H cyclization. This represents first example enantioselective reaction carboranes, providing way for construction compounds skeletons.

Language: Английский

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Pd(ii)-catalyzed synthesis of bifunctionalized carboranesviacage B–H activation of 1-CH₂NH₂-o-carboranes

Chemical Science, Journal Year: 2018, Volume and Issue: 9(16), P. 3964 - 3969

Published: Jan. 1, 2018

Pd-catalyzed, transient group-directed diarylation of cage B(4,5)–H bonds in 1-CH₂NH₂-o-carboranes was reported, including the isolation and structural characterization key intermediates.

Language: Английский

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Recent advances in B–H functionalization of icosahedral carboranes and boranes by transition metal catalysis

Pure and Applied Chemistry, Journal Year: 2018, Volume and Issue: 90(4), P. 733 - 744

Published: Feb. 8, 2018

Abstract Significant progress in the functionalization of icosahedral boron clusters has been made past years, leading to an increasing number applications various fields research. The direct conversion B–H bonds substituted vertices constitutes attractive strategy synthesize cage compounds with desired properties. In this report, recent advances transition metal-catalyzed activation neutral and anionic are presented.

Language: Английский

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