Lewis Base–Boryl Radicals Enabled Borylation Reactions and Selective Activation of Carbon–Heteroatom Bonds

Accounts of Chemical Research, Год журнала: 2022, Номер 56(2), С. 169 - 186

Опубликована: Дек. 26, 2022

ConspectusThe past decades have witnessed tremendous progress on radical reactions. However, in comparison with carbon, nitrogen, oxygen, and other main group element centered radicals, the synthetic chemistry of boron radicals was less studied, mainly due to high electron-deficiency instability such 3-center-5-electron species. In 1980s, Roberts co-workers found that coordination a Lewis base (amines or phosphines) center could form 4-center-7-electron boryl (Lewis base-boryl LBRs) are be more stable. only limited applications were developed. 2008, Curran achieved breakthrough discovery N-heterocyclic carbene (NHC) which enable range reduction polymerization Despite these exciting findings, powerful valuable LBRs would expected, given structures reactivities easily modulated, provide ample opportunities discover new this Account, summary our key contributions LBR-enabled borylation reactions selective activation inert carbon-heteroatom bonds will presented.Organoboron compounds shown versatile chemical society, their syntheses rely principally ionic The development mechanistically different allows synthesizing products inaccessible by traditional methods. For purpose, we progressively developed series NHC-boryl mediated chemo-, regio-, stereoselective alkenes alkynes, wide variety structurally diverse organoboron molecules successfully prepared. utility borylated also demonstrated. Furthermore, disclosed photoredox protocol for oxidative generation enabled useful defluoroborylation arylboration reactions.Selective bond is an ideal way convert simple starting materials value-added products, while cleavage bonds, particular chemoselectivity control when multiple identical present similar environments, remains long-standing challenge. We envisaged finely tuning properties might solution address Recently, 4-dimethylaminopyridine (DMAP)-boryl promoted sequential C-F functionalization trifluoroacetic acid derivatives, α-C-F selectively snipped via spin-center shift mechanism. This strategy enables facile conversion abundantly available highly mono- difluorinated molecules. Encouraged finding, further three-step sequence construct all-carbon quaternary centers from trichloromethyl groups, where three C-Cl cleaved rational choice suitable precursors each step. dehydroxylative alkylation α-hydroxy carboxylic derivatives achieved, allowing efficient some biomass platform value products.

Язык: Английский

---

“Cage Walking” Synthetic Strategy for Unusual Unsymmetrical Supramolecular Cages

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(15), С. 8569 - 8575

Опубликована: Апрель 6, 2023

Developing novel assembly methods for supramolecular compounds has long been a research challenge. Herein, we describe how to integrate the B-C coupling reaction and "cage walking" process into coordination self-assembly construct cages. In this strategy, dipyridine linkers containing alkynes react with metallized carborane backbone through then resulting in metallacages. However, without alkynyl groups can form only metallacycles. We regulate size of metallacages based on length bipyridine linkers. When tridentate-pyridine participate reaction, new type ravel is formed. The metallization carboranes, especially cages play vital role reaction. This work provides promising principle synthesis opens up opportunity field.

Язык: Английский

---

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

---

Organocatalytic Asymmetric Synthesis of o-Carboranyl Amines

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 14, 2025

Carboranyl amines are distinct from typical organic amines. Due to the electronic influence of carborane cage, they have low nucleophilicity and reluctant alkylate. Moreover, asymmetric synthesis chiral carboranes is still in its infancy. Herein we achieved first catalytic N-alkylation o-carboranyl amine, providing general access diverse secondary with high efficiency enantioselectivity under mild conditions. For time, organocatalysis was introduced chemistry. Key success use situ generated (naphtho-)quinone methides as alkylating reagents suitable acid catalysts. This protocol also applicable S-alkylation 1-SH-o-C2B10H11. Control experiments kinetic studies provided important insights into reaction mechanism, which likely involves rate-determining generation quinone methide followed by fast enantio-determining nucleophilic addition.

Язык: Английский

---

Photocatalytic [3 + 2]-annulation via sodium tetraarylborate: a fundamental approach for synthesizing 1,4,2-diazaborole analogs

Chemical Science, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Nitriles stabilize neutral diarylboryl radicals, generating the RCN-BAr 2 complex, an efficient boron-nitrogen synthon that reacts with imines and olefins for photocatalytic synthesis of boron–nitrogen heterocycles, such as 1,4,2-diazaboroles.

Язык: Английский

---

Recent Advances in Carborane-Based Crystalline Porous Materials

Molecules, Год журнала: 2024, Номер 29(16), С. 3916 - 3916

Опубликована: Авг. 19, 2024

The field of carborane research has witnessed continuous development, leading to the construction and development a diverse range crystalline porous materials for various applications. Moreover, innovative synthetic approaches are expanding in this field. Since first report carborane-based (CCPMs) 2007, synthesis ligands, particularly through methods, consistently posed significant challenge discovering new structures CCPMs. This paper provides comprehensive summary recent advances CCPMs, along with their applications different domains. primary challenges future opportunities expected stimulate further multidisciplinary

Язык: Английский

---

Visible‐Light‐Induced Photoreduction of Carborane Phosphonium Salts: Efficient Synthesis of Carborane‐Oxindole‐Pharmaceutical Hybrids

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(31)

Опубликована: Апрель 29, 2023

Visible-light-induced photoreaction of carboranes is an effective approach to prepare carborane-containing compounds. While several methods involving boron-centered carboranyl radicals have been established, those for carbon-centered are underdeveloped, except the UV-light-promoted photohomolysis. Herein, we describe a simple but access by photoreduction carborane phosphonium salts under blue light irradiation without using transition metals and photocatalysts. The utility method was demonstrated successfully preparing range carborane-oxindole-pharmaceutical hybrids radical cascade reactions. Computational experimental studies suggest that generated single-electron transfer photoactive charge-transfer complexes between additive potassium acetate.

Язык: Английский

---

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

---

Visible-light-induced decarboxylation/defluorosilylation protocol for synthesis ofgem-difluoroalkenes

Catalysis Science & Technology, Год журнала: 2023, Номер 13(6), С. 1628 - 1632

Опубликована: Янв. 1, 2023

A catalytic defluorosilylation is disclosed that provides a concise route to gem -difluoroallylsilanes with broad functional-group compatibility from trifluoromethylalkenes and silacarboxylic acids, stable silyl radical precursors.

Язык: Английский

---

Pd(II)-catalyzed B(9)-alkynylation of o/m-carboranes

Organic Chemistry Frontiers, Год журнала: 2024, Номер 11(23), С. 6706 - 6711

Опубликована: Янв. 1, 2024

Pd( ii )-catalyzed selective B(9)-alkynylation of o -carboranes and m with i Pr 3 SiCCBr as the alkynylated reagent was developed. Further transformation products provided diverse carborane derivatives.

Язык: Английский

---