Palladium-Catalyzed Regioselective B(9)-Amination of o-Carboranes and m-Carboranes in HFIP with Broad Nitrogen Sources

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(18), С. 8371 - 8378

Опубликована: Май 2, 2022

Amination of carboranes has a good application prospect in organic and pharmaceutical synthesis. However, the current methods used for this transformation suffer from limitations. Herein, we report practical method highly regioselective formation B-N bond by Pd(II)-catalyzed B(9)-H amination o- m-carboranes hexafluoroisopropanol (HFIP) with different nitrogen sources under air atmosphere. The silver salt HFIP solvent play critical roles present protocol. mechanistic study reveals that acts as Lewis acid to promote electrophilic palladation step forming heterobimetallic active catalyst PdAg(OAc)3; strong hydrogen-bond-donating ability low nucleophilicity enhance Pd(II). It is believed these N-containing are potentially great importance synthesis new pharmaceuticals.

Язык: Английский

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

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(13), С. 7331 - 7342

Опубликована: Март 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.

Язык: Английский

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Photoinduced Selective B–H Activation of nido-Carboranes

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(11), С. 7791 - 7802

Опубликована: Март 10, 2024

The development of new synthetic methods for B–H bond activation has been an important research area in boron cluster chemistry, which may provide opportunities to broaden the application scope clusters. Herein, we present a reaction strategy direct site-selective functionalization nido-carboranes initiated by photoinduced cage via noncovalent cage···π interaction. As result, nido-carborane radical is generated through single electron transfer from 3D 2D photocatalyst upon irradiation with green light. resulting transient could be directly probed advanced time-resolved EPR technique. In air, subsequent transformations active have led efficient and selective B–N, B–S, B–Se couplings presence N-heterocycles, imines, thioethers, thioamides, selenium ethers. This protocol also facilitates both late-stage modification drugs synthesis nido-carborane-based drug candidates neutron capture therapy (BNCT).

Язык: Английский

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A variable bidentate traceless directing group for nickel-catalyzed regioselective B–H poly-chalcogenation of o-carboranes

Inorganic Chemistry Frontiers, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

A nickel-catalyzed direct cage B–H poly-chalcogenation of icosahedral carborane clusters, enabled by a variable bidentate 8-aminoquinoline traceless directing group, has been developed under oxidant-free and weakly basic conditions.

Язык: Английский

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Iridium-Catalyzed Selective B(4)–H Acylmethylation of o-Carboranes with Sulfoxonium Ylides

Organic Letters, Год журнала: 2022, Номер 24(6), С. 1318 - 1322

Опубликована: Фев. 7, 2022

A highly efficient Ir-catalyzed regioselective cage B(4)-H acylmethylation of o-carboranyl acids using sulfoxonium ylides as alkylating regents has been developed, leading to the preparation a large class B(4)-acylmethylated o-carboranes in good excellent yields with broad substrate scope under redox neutral conditions. The -COOH moiety serves traceless directing group and controls regioselectivity monoselectivity.

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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Couple-close construction of non-classical boron cluster-phosphonium conjugates

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Сен. 11, 2024

Язык: Английский

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Highly selective electrophilic B(9)-amination of o-carborane driven by HOTf and HFIP

Organic Chemistry Frontiers, Год журнала: 2022, Номер 9(18), С. 4975 - 4980

Опубликована: Янв. 1, 2022

An efficient B(9) electrophilic amination of o -carboranes with azodicarboxylates, promoted by a Brønsted acid and HFIP, was developed.

Язык: Английский

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A strategy for regioselective B–H functionalization ofo-carboranesviabase metal catalysis

Organic Chemistry Frontiers, Год журнала: 2023, Номер 10(12), С. 3074 - 3079

Опубликована: Янв. 1, 2023

This frontier article summarizes the recent developments in base metal-catalyzed regioselective cage B–H functionalization of carboranes and discusses related challenging issues.

Язык: Английский

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Application of the aza-Wittig reaction for the synthesis of carboranyl Schiff bases, benzothiazoles and benzoselenazolines

Dalton Transactions, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

The aza-Wittig reaction was successfully applied to the synthesis of carboranyl-imines, which are difficult obtain by classical methods. A variety functionalized carboranyl Schiff bases obtained proving great scope methodology. All compounds were fully characterized, including solid-state structures six them. modified permit in one step carboranyl-benzothiazole and carboranyl-benzoselenazoline derivatives. stability studies show that carboranyl-imines benzothiazole promote deboronation nido-derivatives, is achieved simple with methanol or protic solvents. nido-derivatives also studied X-ray diffraction. In contrast, saturated derivatives, amine benzoselenazoline, do not stable

Язык: Английский

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