Catalyst-Free and Redox-Neutral Innate Trifluoromethylation and Alkylation of Aromatics Enabled by Light

Journal of the American Chemical Society, Год журнала: 2017, Номер 139(40), С. 14315 - 14321

Опубликована: Окт. 1, 2017

The Minisci alkylation is useful to functionalize aromatics via alkyl radical addition. Current approaches prepare radicals follow either oxidative or reductive pathways from various functional groups. Developing new strategy beyond these traditional methods remains elusive yet highly significant. In this article, we present a redox-neutral and catalyst-free protocol engender in the context of trifluoromethylation general arenes. This protocol, Norrish type I concept produce radicals, accommodates groups delivers product good yields. method identified series compounds as reagents assisted by light. It expected that can find potential applications other radical-involved reactions.

Язык: Английский

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Electrophotocatalytic Undirected C−H Trifluoromethylations of (Het)Arenes

Chemistry - A European Journal, Год журнала: 2019, Номер 26(15), С. 3241 - 3246

Опубликована: Дек. 25, 2019

Electrophotochemistry has enabled arene C-H trifluoromethylation with the Langlois reagent CF3 SO2 Na under mild reaction conditions. The merger of electrosynthesis and photoredox catalysis provided a chemical oxidant-free approach for generation radical. electrophotochemistry was carried out in an operationally simple manner, setting stage challenging trifluoromethylations unactivated arenes heteroarenes. robust nature electrophotochemical manifold reflected by wide scope, including electron-rich electron-deficient benzenes, as well naturally occurring Electrophotochemical further achieved flow modular electro-flow-cell equipped in-operando monitoring unit on-line flow-NMR spectroscopy, providing support single electron transfer processes.

Язык: Английский

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Site-Selective Direct C–H Pyridylation of Unactivated Alkanes by Triplet Excited Anthraquinone

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(7), С. 3003 - 3012

Опубликована: Фев. 8, 2021

Site-selective C-H functionalization in chemical feedstocks is a challenging and useful reaction the broad field of research. Here, we report modular photochemical platform for site-selective pyridylation unactivated hydrocarbons via unique synergistic effects triplet excited anthraquinone an amidyl radical-based reverse hydrogen atom transfer (RHAT) agent. The selective tertiary secondary C(sp3)-H bonds abundant was achieved by employing various N-aminopyridinium salts highly fashion, thus providing new catalytic system direct construction high-value-added compounds under ambient conditions. Moreover, this operationally simple protocol applicable to variety linear-, branched-, cyclo-alkanes more complex molecules with high degrees site selectivity visible-light conditions, which provides rapid straightforward access versatile synthons upgrading mild, metal-free

Язык: Английский

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A cross-dehydrogenative C(sp3)−H heteroarylation via photo-induced catalytic chlorine radical generation

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Июнь 29, 2021

Abstract Hydrogen atom abstraction (HAT) from C( sp 3 )–H bonds of naturally abundant alkanes for alkyl radical generation represents a promising yet underexplored strategy in the alkylation reaction designs since involving stoichiometric oxidants, excessive alkane loading, and limited scope are common drawbacks. Here we report photo-induced chemical oxidant-free cross-dehydrogenative coupling (CDC) between heteroarenes using catalytic chloride cobalt catalyst. Couplings strong bond-containing substrates complex heteroarenes, have been achieved with satisfactory yields. This dual platform features situ engendered chlorine exploits cobaloxime catalyst to enable hydrogen evolution turnover. The practical value this protocol was demonstrated by gram-scale synthesis alkylated heteroarene merely equiv. loading.

Язык: Английский

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Direct Decarboxylation of Trifluoroacetates Enabled by Iron Photocatalysis**

Angewandte Chemie International Edition, Год журнала: 2023, Номер 63(5)

Опубликована: Дек. 13, 2023

Trifluoroacetates are the most abundant and accessible sources of trifluoromethyl groups, which key components in pharmaceuticals agrochemicals. The generation reactive radicals from trifluoroacetates requires their decarboxylation, is hampered by high oxidation potential. This constitutes a major challenge for redox-based methods, because need to pair redox potentials with trifluoroacetate. Here we report strategy based on iron photocatalysis promote direct photodecarboxylation that displays reactivity features escape limitations. Our synthetic design has enabled use trifluoromethylation more easily oxidizable organic substrates, offering new opportunities late-stage derivatization campaigns using chemical feedstocks, Earth-abundant catalysts, visible-light.

Язык: Английский

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Scalable decarboxylative trifluoromethylation by ion-shielding heterogeneous photoelectrocatalysis

Science, Год журнала: 2024, Номер 384(6696), С. 670 - 676

Опубликована: Май 9, 2024

Electrochemistry offers a sustainable synthesis route to value-added fine chemicals but is often constrained by competing electron transfer between the electrode and redox-sensitive functionalities distinct from target site. Here, we describe an ion-shielding heterogeneous photoelectrocatalysis strategy impose mass-transfer limitations that invert thermodynamically determined order of transfer. This showcased enable decarboxylative trifluoromethylation sensitive (hetero)arenes using trifluoroacetate, inexpensive yet relatively inert trifluoromethyl group (CF

Язык: Английский

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Promoting Photocatalytic Direct C–H Difluoromethylation of Heterocycles using Synergistic Dual-Active-Centered Covalent Organic Frameworks

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(18), С. 12386 - 12394

Опубликована: Март 19, 2024

Difluoromethylation reactions are increasingly important for the creation of fluorine-containing heterocycles, which core groups in a diverse range biologically and pharmacologically active ingredients. Ideally, this typically challenging reaction could be performed photocatalytically under mild conditions. To achieve separation redox processes would required efficient generation difluoromethyl radicals reduction oxygen. A covalent organic framework photocatalytic material was, therefore, designed with dual reactive centers. Here, anthracene was used as site benzothiadiazole an oxidation site, distributed tristyryl triazine framework. Efficient charge ensured by superior electron-donating -accepting abilities centers, creating long-lived photogenerated electron–hole pairs. Photocatalytic difluoromethylation 16 compounds high yields remarkable functional group tolerance demonstrated; included bioactive molecules such xanthine uracil. The structure–function relationship dual-active-center photocatalyst investigated through electron spin resonance, femtosecond transient absorption spectroscopy, density theory calculations.

Язык: Английский

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Review and Theoretical Analysis of Fluorinated Radicals in Direct C_Ar−H Functionalization of (Hetero)arenes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(16)

Опубликована: Янв. 29, 2024

Abstract We highlight key contributions in the field of direct radical C Ar − H (hetero)aromatic functionalization involving fluorinated radicals. A compilation Functional Group Transfer Reagents and their diverse activation mechanisms leading to release radicals are discussed. The substrate scope for each is analyzed classified into three categories according electronic properties substrates. Density functional theory computational analysis provides insights chemical reactivity several through electrophilicity nucleophilicity parameters. Theoretical reduction potentials also highlights remarkable correlation between oxidizing ability. It established that highly (e.g. ⋅OCF 3 ) capable engaging single‐electron transfer (SET) processes rather than addition, which good agreement with experimental literature data. scale, based on barrier addition these benzene elaborated using high accuracy DLPNO‐(U)CCSD(T) method.

Язык: Английский

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Visible-light-induced oxidant and metal-free dehydrogenative cascade trifluoromethylation and oxidation of 1,6-enynes with water

Chemical Science, Год журнала: 2017, Номер 8(9), С. 6633 - 6644

Опубликована: Янв. 1, 2017

Unprecedented light-induced oxidant and metal-free tandem radical cyclization–trifluoromethylation dehydrogenative oxygenation of 1,6-enynes have been achieved using a photoredox catalyst, CF₃SO₂Na, water as the oxygen source.

Язык: Английский

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Diacetyl as a “traceless” visible light photosensitizer in metal-free cross-dehydrogenative coupling reactions

Chemical Science, Год журнала: 2019, Номер 10(19), С. 5018 - 5024

Опубликована: Янв. 1, 2019

Minisci alkylation is of prime importance for its applicability in functionalizing diverse heteroarenes, which are core structures many bioactive compounds.

Язык: Английский

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