Alkyl Radical Generation from Alkylboronic Pinacol Esters through Substitution with Aminyl Radicals

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(16), С. 8770 - 8775

Опубликована: Апрель 14, 2023

Alkylboronic pinacol esters (APEs) are highly versatile reagents in organic synthesis. However, the direct generation of alkyl radicals from commonly used, bench-stable APEs has not been well explored. In this communication, radical through reaction with aminyl is reported. The readily generated by visible-light-induced homolytic cleavage N-N bond N-nitrosamines, and C occurs nucleohomolytic substitution at boron. As an application, efficient photochemical alkyloximation alkenes N-nitrosamines under mild conditions presented. A wide range primary, secondary, tertiary engage transformation that easily scaled up.

Язык: Английский

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Zinc Catalyzed Hydroelementation (HE; E = B, C, N, and O) of Carbodiimides: Intermediates Isolation and Mechanistic Insights

Organometallics, Год журнала: 2023, Номер 42(14), С. 1746 - 1758

Опубликована: Март 15, 2023

The conjugated bis-guanidinate (CBG) supported zinc hydride, [{LZnH}2; L = {(ArHN)(ArN)-C═N–C═(NAr)(NHAr); Ar 2,6-Et2-C6H3}] (1) (pre)-catalyzed addition of E–H (E B, C, N, and O) to carbodiimides is presented. Compound 1 catalyzed the reduction with pinacolborane (HBpin), terminal alkynes, primary amines, alcohols, gave a series N-boryl formamidines, propiolamidines, guanidines, isoureas high conversions. All these reactions display good tolerance functional groups. These proceeded through active catalysts intermediate amidinate (Zn-1, Zn-1′, Zn-3), alkynyl (Zn-2, Zn-2′), anilide (Zn-4), alkoxide (Zn-5) complexes, which have been characterized by multinuclear NMR HRMS analyses. Moreover, compounds Zn-2′, Zn-4, Zn-5 were confirmed single-crystal X-ray diffraction studies. Complete catalytic cycles proposed based on well-defined intermediates stoichiometric experiments.

Язык: Английский

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Deboronative functionalization of alkylboron species via a radical-transfer strategy

Chemical Science, Год журнала: 2024, Номер 15(35), С. 14241 - 14247

Опубликована: Янв. 1, 2024

We describe a method for activating C–B bonds by nitrogen- or oxygen-radical transfer that is applicable to alkylboronic acids and esters.

Язык: Английский

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Fluorenyl-tethered N-heterocyclic carbene: An effective ancillary support for heteroleptic magnesium organometallics

Polyhedron, Год журнала: 2024, Номер 251, С. 116849 - 116849

Опубликована: Янв. 21, 2024

Язык: Английский

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Visible-Light-Induced trans-Hydroboration of Diaryl Alkynes Utilizing Excited State of Borate Complexes

Organic Letters, Год журнала: 2024, Номер 26(11), С. 2180 - 2185

Опубликована: Март 11, 2024

We have developed visible-light-induced trans-hydroboration of diaryl alkynes via direct photoexcitation in-situ-generated diboron complexes, affording previously elusive (E)-1,2-diaryl-vinylboronates with high stereoselectivity. Experimental, spectroscopic, and theoretical mechanistic studies revealed that the triplet-state borate complex facilitates B–B bond cleavage desired C–B formation. This methodology does not require any catalyst is operationally simple. The highly borylated 1,2-diaryl alkenes [1-(2-borylphenyl)vinyl)boronates] are shown to be useful as building blocks.

Язык: Английский

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Photochemical C–H Borylation in Organic Synthesis

ACS Catalysis, Год журнала: 2025, Номер 15(3), С. 1753 - 1770

Опубликована: Янв. 16, 2025

Although C–H bond functionalization has been extensively studied since its discovery in 1955, the borylation of organic compounds by activating bonds only became popular valuable Hartwig 1995 who considered a wider application these transformations synthetic chemistry. For borylation, catalytic activation this generally low-reactivity can be performed many ways. Among approaches reported are use and stoichiometric reagents, thermal activation, photochemical suitable substrates. Iridium-, ruthenium-, rhodium-based protocols using have played crucial role toward establishment area. Photochemical though, scarcely explored despite fact that it represents comparably environmentally benign protocol light as renewable energy source. In literature survey, we highlight recent developments from initial inception up to latest advancements.

Язык: Английский

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Synthesis, Characterization, and Reactivity of Aminotroponiminate-Based Difluoroboranes: A Pathway toward Bore(boro)nium Cations

Inorganic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Май 10, 2025

Aminotroponiminates (ATIs), a well-known monoanionic bidentate ligand, display wide range of coordination chemistry. To exploit their electronic and steric factors in achieving boron cations, series symmetrical, unsymmetrical, bis(ATI) borane complexes [(C7H5)(NiPr)2BF2] (3a), [(C7H5)(NtBu)2BF2] (3b), [(C7H5)(NiBu)2BF2] (3c), [(C7H5)(NiBu)(NtBu)BF2] (3d), [(C7H5)(NiPr)(NCH2)BF2]2 (3e) were synthesized this work. All the ATI are highly blue luminescent solution, fluorescence decay time was recorded DCM. The observed found to exist between 1.7 2.8 ns. Complexes 3a 3b when treated with trimethylsilyl triflate (TMS-OTf) enabled isolation tricoordinated borenium cations [(C7H5)(NiPr)2BOH]+ (4a) [(C7H5)(NtBu)2BOH]+ (4b), respectively. Interestingly, reaction 3e TMS-OTf resulted dication 4e which boronium bridged via an oxygen atom seven-membered ring scaffold. boranes well characterized by various spectroscopic techniques solution X-ray structure diffraction analysis solid state. Further, theoretical calculations using density functional theory (DFT) conducted understand bonding scenario these complexes.

Язык: Английский

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Magnesium halide-catalyzed hydroboration of isocyanates and ketones

Organic & Biomolecular Chemistry, Год журнала: 2023, Номер 21(17), С. 3628 - 3635

Опубликована: Янв. 1, 2023

Alkaline-earth metals have attracted increasing attention because they are cheap, Earth abundant and environmentally friendly, gradually become inexpensive sustainable alternatives to traditional precious transition metal catalysts in many organic reactions. Recently, the hydroboration of unsaturated substrates has been extensively investigated. However, reports on alkaline-earth catalyzed isocyanates ketones rare. Herein, we report that simple, commercially available, air-stable magnesium halides successfully employed as highly efficient ketones. Various boronate products were obtained high yields with low catalyst loading under mild conditions.

Язык: Английский

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Metal-free C–H Borylation and Hydroboration of Indoles

ACS Omega, Год журнала: 2023, Номер 8(41), С. 37623 - 37640

Опубликована: Окт. 2, 2023

The C–H borylation and hydroboration reactions have emerged as promising synthetic tools to construct organoboron compounds. Organoboron compounds of N-heterocycles, particularly indole derivatives, found widespread application in a variety fields. As result, considerable advancement the area indoles was observed last few decades. Among various methods applied, metal-free approach has received special attention. This mini-review discusses recent progress under conditions, their scope, brief mechanistic studies.

Язык: Английский

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Catalytic hydroboration of aldehydes and ketones with an electron-rich acyclic metallasilylene

Chemical Science, Год журнала: 2024, Номер 15(11), С. 4161 - 4170

Опубликована: Янв. 1, 2024

Catalytic hydroboration of aldehydes and ketones is achieved with alkoxysilylene 2. Quantum chemical calculations gave insights into the energetics its formation provide possible catalytic reaction mechanism.

Язык: Английский

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