Red Light–Blue Light Chromoselective C(sp²)–X Bond Activation by Organic Helicenium-Based Photocatalysis

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(12), С. 7922 - 7930

Опубликована: Март 18, 2024

Chromoselective bond activation has been achieved in organic helicenium (nPr-DMQA+)-based photoredox catalysis. Consequently, control over chromoselective C(sp2)–X multihalogenated aromatics demonstrated. nPr-DMQA+ can only initiate the halogen atom transfer (XAT) pathway under red light irradiation to activate low-energy-accessible C(sp2)–I bonds. In contrast, blue initiates consecutive photoinduced electron (conPET) more challenging C(sp2)–Br Comparative reaction outcomes have demonstrated α-arylation of cyclic ketones with and lights. Furthermore, red-light-mediated selective bonds activated iodobromoarenes keep bromo functional handle untouched. Finally, strength catalysis highlighted two-fold functionalization using both photo-to-transition metal photo-to-photocatalyzed transformations.

Язык: Английский

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Red light excitation: illuminating photocatalysis in a new spectrum

Beilstein Journal of Organic Chemistry, Год журнала: 2025, Номер 21, С. 296 - 326

Опубликована: Фев. 7, 2025

Red-light-activated photocatalysis has become a powerful approach for achieving sustainable chemical transformations, combining high efficiency with energy-saving, mild conditions. By harnessing the deeper penetration and selectivity of red near-infrared light, this method minimizes side reactions typical higher-energy sources, making it particularly suited large-scale applications. Recent advances highlight unique advantages both metal-based metal-free catalysts under red-light irradiation, broadening range possible reactions, from selective oxidations to complex polymerizations. In biological contexts, enables innovative applications in phototherapy controlled drug release, exploiting its tissue low cytotoxicity. Together, these developments underscore versatility impact photocatalysis, positioning as cornerstone green organic chemistry significant potential synthetic biomedical fields.

Язык: Английский

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Red-Light-Active N,C,N-Pincer Bismuthinidene: Excited State Dynamics and Mechanism of Oxidative Addition into Aryl Iodides

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

Опубликована: Фев. 10, 2025

Despite the progress made in field of synthetic organic photocatalysis over past decade, use higher wavelengths, especially those deep-red portion electromagnetic spectrum, remains comparatively rare. We have previously disclosed that a well-defined N,C,N-pincer bismuthinidene (1a) can undergo formal oxidative addition into wide range aryl electrophiles upon absorption low-energy red light. In this study, we map out photophysical dynamics 1a and glean insights nature excited state responsible for activation electrophiles. Transient emission techniques reveal that, irradiation with light, complex undergoes direct S0 → S1 metal-to-ligand charge transfer (MLCT) transition, followed by rapid intersystem crossing (ISC) to highly reducing emissive triplet (−2.61 V vs Fc+/0 MeCN). The low dissipative losses incurred during ISC (∼6% incident light energy) help rationalize ability convert useful chemical energy. Spectroelectrochemical computational data support charge-separated excited-state structure radical-anion character on ligand radical-cation bismuth. Kinetic studies competition experiments afford mechanism iodides; concerted inner-sphere processes from are ruled out, strongly supporting pathway proceeds via outer-sphere dissociative electron transfer.

Язык: Английский

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Synthetic Applications of Sulfonium Salts as Aryl Radical Precursors

European Journal of Organic Chemistry, Год журнала: 2023, Номер 26(43)

Опубликована: Сен. 13, 2023

Abstract The utilization of aryl radicals as open‐shelled intermediates has become an essential tool for both conventional and state‐of‐the‐art synthetic chemistry. However, the current methods generating are still inefficient, greatly impeding their practical applications. Encouragingly, sulfonium salts have emerged appealing sources a wide range transformations aimed at creating novel chemical bonds driven by distinctive structural attributes tendencies. This review primarily focuses on specific reaction mechanisms underlying cleavage C−S in salts, leading to generation corresponding within diverse conditions.

Язык: Английский

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Bi-Catalyzed Trifluoromethylation of C(sp²)–H Bonds under Light

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(47), С. 25538 - 25544

Опубликована: Ноя. 14, 2023

We disclose a Bi-catalyzed C–H trifluoromethylation of (hetero)arenes using CF3SO2Cl under light irradiation. The catalytic method permits the direct functionalization various heterocycles bearing distinct functional groups. structural and computational studies suggest that process occurs through an open-shell redox manifold at bismuth, comprising three unusual elementary steps for main group element. cycle starts with rapid oxidative addition to low-valent Bi(I) catalyst, followed by light-induced homolysis Bi(III)–O bond generate trifluoromethyl radical upon extrusion SO2, is closed hydrogen-atom transfer Bi(II) intermediate.

Язык: Английский

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Bismuth in Radical Chemistry and Catalysis

Angewandte Chemie International Edition, Год журнала: 2023, Номер 63(8)

Опубликована: Ноя. 22, 2023

Abstract Whereas indications of radical reactivity in bismuth compounds can be traced back to the 19 th century, preparation and characterization both transient persistent bismuth‐radical species has only been established recent decades. These advancements led emergence field chemistry, mirroring progress seen for other main‐group elements. The seminal fundamental studies this area have ultimately paved way development catalytic methodologies involving intermediates, a promising approach that remains largely untapped broad landscape synthetic organic chemistry. In review, we delve into milestones eventually present state‐of‐the‐art Our focus aims at outlining intrinsic discoveries inorganic/organometallic chemistry contextualizing their practical applications synthesis catalysis.

Язык: Английский

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Low-energy photoredox catalysis

Nature Reviews Chemistry, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 11, 2024

Язык: Английский

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Nitrate reduction enables safer aryldiazonium chemistry

Science, Год журнала: 2024, Номер 384(6694), С. 446 - 452

Опубликована: Апрель 25, 2024

Aryldiazonium salts remain a staple in organic synthesis and are still prepared largely accord with the protocol developed 19th century. Because of favorable reactivity that often cannot be achieved other aryl(pseudo)halides, diazonium chemistry continues to grow. Facile extrusion dinitrogen contributes desired but is also reason for safety concerns. Explosions have occurred since discovery these reagents result accidents. In this study, we report paradigm shift based on nitrate reduction using thiosulfate or dihalocuprates as electron donors avoids accumulation. rate-limiting, aryldiazoniums produced fleeting intermediates, which results safer more efficient deaminative halogenation single step from anilines.

Язык: Английский

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Catalytically Relevant Organocopper(III) Complexes Formed through Aryl-Radical-Enabled Oxidative Addition

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(22), С. 15176 - 15185

Опубликована: Май 21, 2024

Stepwise oxidative addition of copper(I) complexes to form copper(III) species via single electron transfer (SET) events has been widely proposed in copper catalysis. However, direct observation and detailed investigation these fundamental steps remain elusive owing largely the typically slow rate instability species. We report herein a novel aryl-radical-enabled stepwise pathway that allows for formation well-defined alkyl–CuIII from CuI complexes. The process is enabled by SET an aryl diazonium salt CuII radical. Subsequent iodine abstraction alkyl iodide radical affords radical, which then reacts with complex. structure resultant [(bpy)CuIII(CF3)2(alkyl)] characterized NMR spectroscopy X-ray crystallography. Competition experiments have revealed at different iodides undergo consistent carbon-centered radicals. intermediate formed during identified as four-coordinate complex, [CuII(CH3CN)2(CF3)2], through electronic paramagnetic resonance (EPR) studies. catalytic relevance high-valent organo-CuIII demonstrated C–C bond-forming reductive elimination reactivity. Finally, localized orbital bonding analysis formal CuIII indicates inverted ligand fields σ(Cu–CH2) bonds. These results demonstrate catalysis provide general strategy investigate

Язык: Английский

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Organobismuth Compounds as Aryl Radical Precursors via Light-Driven Single-Electron Transfer

ACS Catalysis, Год журнала: 2024, Номер 14(4), С. 2664 - 2670

Опубликована: Фев. 6, 2024

A light-driven method for the generation of aryl radicals from triarylbismuth(III) and (V) reagents is described. Aryl radical proposed to occur through ligand-assisted mesolytic cleavage an organobismuth(IV) intermediate generated either oxidation BiIII or reduction BiV. This mode demonstrated be compatible with a range bimolecular arylations, including hydroarylation electron-deficient olefins arylation diboronates, disulfides, sulfonyl cyanides, phosphites, isocyanides. The intermediacy supported by trapping clock experiments, BiIV–aryl mesolysis computationally.

Язык: Английский

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