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

Accounts of Chemical Research, Год журнала: 2021, Номер 54(21), С. 4065 - 4079

Опубликована: Окт. 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.

Язык: Английский

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

Bulletin of the Chemical Society of Japan, Год журнала: 2020, Номер 94(3), С. 879 - 899

Опубликована: Дек. 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.

Язык: Английский

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Functional Group Directed B–H Activation of Polyhedral Boron Hydrides by Transition Metal Complexes (Review)

Russian Journal of Inorganic Chemistry, Год журнала: 2021, Номер 66(9), С. 1289 - 1342

Опубликована: Сен. 1, 2021

Язык: Английский

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

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(11), С. 4148 - 4153

Опубликована: Март 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.

Язык: Английский

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Iridium(III)-Catalyzed B(4)-Acylmethylation and B(3,5)-Diacylmethylation from o-Carboranes and Sulfoxonium Ylides

Organic Letters, Год журнала: 2022, Номер 24(8), С. 1604 - 1609

Опубликована: Фев. 17, 2022

An iridium(III)-catalyzed regioselective acylmethylation of the cage B(4)-H bond in o-carborane acids with sulfoxonium ylides is demonstrated through activation ethanol under very mild conditions, affording a number B(4)-acylmethylated o-carboranes. Additionally, selective sequential B(4)- and B(6)-acylmethylation reactions finally gave B(3,5)-diacylmethylated o-carboranes one pot.

Язык: Английский

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8-Aminoquinoline as a bidentate traceless directing group for Cu-catalyzed selective B(4,5)–H disulfenylation ofo-carboranes

Chemical Communications, Год журнала: 2020, Номер 56(85), С. 12997 - 13000

Опубликована: Янв. 1, 2020

A traceless bidentate directing group guided copper catalyzed direct cage B(4,5)-H disulfenylation of o-carboranes has been achieved, leading to a series B(4,5)-disulfenylated o-carborane derivatives in high yields with excellent regioselectivity. The situ departure the 8-aminoquinoline auxiliary circumvents additional processes for removal, thus enhancing atom-/step-economy.

Язык: Английский

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Catalytic Cage BH Functionalization of Carboranes via “Cage Walking” Strategy

ACS Catalysis, Год журнала: 2021, Номер 11(4), С. 2134 - 2140

Опубликована: Фев. 3, 2021

Carboranes, three-dimensional analogues of benzene, are finding a wide variety applications ranging from functional materials to pharmaceuticals, which has drawn tremendous research interest. The recent development transition-metal-catalyzed cage B–H functionalization can realize series vertex-specific carboranes, the "cage-walking" strategy provide BH at different positions where initial bond activation occurs achieve functionalized carboranes that difficult access by conventional methods. In this Viewpoint, we will discuss concept cage-walking and its application in selective highlighting typical examples, could some valuable insights into future carborane multifunctionalization.

Язык: Английский

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Recent Advance in Transition Metal‐Catalyzed Carboxylic Acid Guided B−H Functionalization of Carboranes

Advanced Synthesis & Catalysis, Год журнала: 2022, Номер 364(24), С. 4174 - 4188

Опубликована: Дек. 1, 2022

Abstract Carboranes, a three‐dimensional class of carbon‐boron molecular clusters with remarkable electronic, physical, chemical characteristics, have proved as useful building blocks in boron neutron capture therapy agents, supramolecular design, optoelectronics, nanomaterials and organometallic/coordination chemistry. Thus, various organic modifications the B−H C−H functionalities carboranes been developed. These methods great success utilize directing groups, such carboxylic acids, to achieve selective functionalization carboranes. The carboxyl group can be easily introduced then removed after reactions. On other hand, assisted by highly regioselective electrophilic attack at electron‐rich positions B(4) B(5) cage generates five‐membered metallacyclic intermediates, which undergo further transformation. In this review, we show that transition metal‐catalyzed decarboxylation cross coupling reactions offer an opportunity for direct activation magnified image

Язык: Английский

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Chemodivergent Synthesis of Indeno[1,2-b]indoles and Isoindolo[2,1-a]indoles via Mn(III)-Mediated or Electrochemical Intramolecular Radical Cross-Dehydrogenative Coupling

The Journal of Organic Chemistry, Год журнала: 2022, Номер 87(16), С. 10967 - 10981

Опубликована: Июль 28, 2022

Chemodivergent synthesis of indeno[1,2-b]indoles and isoindolo[2,1-a]indoles from the same starting materials involving radical cross-dehydrogenative couplings have been developed. Mn(OAc)3·2H2O selectively promoted an intramolecular C–H/C–H dehydrogenative coupling reaction to provide indeno[1,2-b]indoles, while C–H/N–H could proceed via electrochemistry deliver isoindolo[2,1-a]indoles. Plausible mechanisms chemodivergent reactions were proposed.

Язык: Английский

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Palladium‐Catalyzed Carbonylative Annulation of 1‐Hydroxy‐o‐Carborane and Internal Alkynes via Regioselective B‐H Activation

Chemistry - An Asian Journal, Год журнала: 2020, Номер 15(14), С. 2170 - 2173

Опубликована: Июнь 13, 2020

A Pd-catalyzed three-component carbonylative-annulation of 1-hydroxy-o-carborane, internal alkyne and carbon monoxide has been achieved via direct regioselective cage B-H activation. class C,B-substituted carborano-coumarin derivatives with potential applications in pharmaceuticals were facilely prepared moderate to high yields excellent chemoselectivity regioselectivity. plausible reaction mechanism including CO insertion, electrophilic metalation, insertion reductive elimination was proposed.

Язык: Английский

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