Nitrogen-Centered Radicals in Functionalization of sp² Systems: Generation, Reactivity, and Applications in Synthesis

Chemical Reviews, Год журнала: 2022, Номер 122(9), С. 8181 - 8260

Опубликована: Март 14, 2022

The chemistry of nitrogen-centered radicals (NCRs) has plentiful applications in organic synthesis, and they continue to expand as our understanding these reactive species increases. utility intermediates is demonstrated the recent advances C–H amination (di)amination alkenes. Synthesis previously challenging structures can be achieved by efficient functionalization sp2 moieties without prefunctionalization, allowing for faster more streamlined synthesis. This Review addresses generation, reactivity, application NCRs, including, but not limited to, iminyl, aminyl, amidyl, aminium species. Contributions from early discovery up most examples have been highlighted, covering radical initiation, thermolysis, photolysis, and, recently, photoredox catalysis. Radical-mediated intermolecular (hetero)arenes occur with a variety complex amine precursors, generating aniline derivatives, an important class drug development. Functionalization olefins achievable high anti-Markovnikov regioselectivity allows access difunctionalized when intermediate carbon are trapped. Additionally, reactivity NCRs harnessed rapid construction N-heterocycles such pyrrolidines, phenanthridines, quinoxalines, quinazolinones.

Язык: Английский

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Supramolecular Coordination Cages for Artificial Photosynthesis and Synthetic Photocatalysis

Chemical Reviews, Год журнала: 2023, Номер 123(9), С. 5225 - 5261

Опубликована: Янв. 20, 2023

Because sunlight is the most abundant energy source on earth, it has huge potential for practical applications ranging from sustainable supply to light driven chemistry. From a chemical perspective, excited states generated by make thermodynamically uphill reactions possible, which forms basis storage into fuels. In addition, with light, open-shell species can be open up new reaction pathways in organic synthesis. Crucial are photosensitizers, absorb and transfer substrates various mechanisms, processes that highly depend distance between molecules involved. Supramolecular coordination cages well studied synthetically accessible vessels single cavities guest binding, ensuring close proximity of different components. Due high modularity their size, shape, nature metal centers ligands, ideal platforms exploit preorganization photocatalysis. Herein we focus application supramolecular photocatalysis artificial photosynthesis photo(redox) catalysis. Finally, brief overview immobilization strategies provides tools implementing devices. This review inspiration future design photocatalytic host-guest systems producing solar fuels complex molecules.

Язык: Английский

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N–O Bond Activation by Energy Transfer Photocatalysis

Accounts of Chemical Research, Год журнала: 2022, Номер 55(17), С. 2526 - 2541

Опубликована: Авг. 20, 2022

ConspectusA radical shift toward energy transfer photocatalysis from electron under visible-light photoirradiation is often due to the greener prospects of atom and process economy. Recent advances in embrace unique strategies for direct small-molecule activation sometimes extraordinary chemical bond formation absence additional/sacrificial reagents. Selective requires careful selection substrates photocatalysts a perfect match with respect their triplet energies while having incompatible redox potentials prevent competitive pathways. Substrates containing labile N–O bonds are potential targets generating reactive key intermediates via access variety functionalized molecules. Typically, differential densities N O heteroatoms have been exploited generation either N- or O-centered by pathway. However, latest developments involve homolysis generate both radicals subsequent utilization diverse organic transformations, also sacrificial In this Account, we highlight our contributions field intermediates, coverage useful mechanistic insights. More specifically, well-designed bond-containing such as 1,2,4-oxadiazolines, oxime esters, N-indolyl carbonates, N-enoxybenzotriazoles were successfully utilized versatile transformations involving selective over high state energy. Direct N-, O-, C-centered (if decarboxylation follows) was achieved cross-couplings rearrangement processes. particular, open-shell nitrogen including N(sp2) N(sp3) nitrenes, utilized. Notably, diversified identical through control reaction conditions. 1,2,4-Oxadiazolines converted into spiro-azolactams iminyl presence 1O2, benzimidazoles, sulfoximines external sulfoxide reagent nitrene inert Besides, esters underwent intramolecular C(sp3)–N radical–radical coupling intermolecular combined transfer–hydrogen strategy. Furthermore, series electrochemical photophysical experiments well computational studies performed substantiate proposed energy-transfer-driven We hope that Account will serve guide rational design processes further bonds.

Язык: Английский

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Using enzymes to tame nitrogen-centred radicals for enantioselective hydroamination

Nature Chemistry, Год журнала: 2022, Номер 15(2), С. 206 - 212

Опубликована: Ноя. 14, 2022

Язык: Английский

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Resurgence and advancement of photochemical hydrogen atom transfer processes in selective alkane functionalizations

Chemical Science, Год журнала: 2023, Номер 14(25), С. 6841 - 6859

Опубликована: Янв. 1, 2023

The selective functionalization of alkanes has long been recognized as a prominent challenge and an arduous task in organic synthesis. Hydrogen atom transfer (HAT) processes enable the direct generation reactive alkyl radicals from feedstock have successfully employed industrial applications such methane chlorination process,

Язык: Английский

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Anti-Markovnikov Intermolecular Hydroamination of Alkenes and Alkynes: A Mechanistic View

Chemical Reviews, Год журнала: 2023, Номер 123(15), С. 9139 - 9203

Опубликована: Июль 5, 2023

Hydroamination, the addition of an N–H bond across a C–C multiple bond, is reaction with great synthetic potential. Important advances have been made in last decades concerning catalysis these reactions. However, controlling regioselectivity amine toward formation anti-Markovnikov products (addition to less substituted carbon) still remains challenge, particularly intermolecular hydroaminations alkenes and alkynes. The goal this review collect systems which hydroamination terminal alkynes has achieved. focus will be placed on mechanistic aspects such reactions, discern step at decided unravel factors that favor regioselectivity. In processes entailing direct alternative pathways, involving several reactions accomplish (formal processes), also discussed review. catalysts gathered embrace most metal groups Periodic Table. Finally, section discussing radical-mediated metal-free approaches, as well heterogeneous catalyzed processes, included.

Язык: Английский

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Photocatalytic doping of organic semiconductors

Nature, Год журнала: 2024, Номер 630(8015), С. 96 - 101

Опубликована: Май 15, 2024

Abstract Chemical doping is an important approach to manipulating charge-carrier concentration and transport in organic semiconductors (OSCs) 1–3 ultimately enhances device performance 4–7 . However, conventional strategies often rely on the use of highly reactive (strong) dopants 8–10 , which are consumed during process. Achieving efficient with weak and/or widely accessible under mild conditions remains a considerable challenge. Here, we report previously undescribed concept for photocatalytic OSCs that uses air as oxidant (p-dopant) operates at room temperature. This general can be applied various photocatalysts, yielding electrical conductivities exceed 3,000 S cm –1 We also demonstrate successful reduction (n-doping) simultaneous p-doping n-doping salt used maintain charge neutrality only chemical consumed. Our method offers great potential advancing OSC developing next-generation electronic devices.

Язык: Английский

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Recent Advances in Electron Donor‐Acceptor (EDA)‐Complex Reactions involving Quaternary Pyridinium Derivatives

Advanced Synthesis & Catalysis, Год журнала: 2023, Номер 365(10), С. 1538 - 1564

Опубликована: Март 6, 2023

Abstract Quaternary pyridinium compounds are valuable intermediates in organic synthesis, which have gained immense popularity the synthetic community. The application of transition metal or photoredox catalysis transforming quaternary into various C−C and C−X bonds is well established. A majority these methods require high temperatures, expansive catalysts, delicate conditions for successful execution. On other hand, use metal‐free photocatalysis‐free strategies constructing using derivatives has been sought‐after. In this context, electron‐donor‐acceptor (EDA)‐complex reactions emerged as a state‐of‐the‐art methodology, do not any photocatalyst their EDA‐complex photochemistry takes advantage electron‐acceptor ability derivatives, can quickly generate radical precursor via deaminative process. These newly generated useful several transformations. We hereby, review, discuss an area major progress mediated involving with mechanism, substrate scope, limitations. magnified image

Язык: Английский

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Copper-catalysed dehydrogenation or lactonization of C(sp3)–H bonds

Nature, Год журнала: 2024, Номер 629(8011), С. 363 - 369

Опубликована: Март 28, 2024

Язык: Английский

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Light-activated hypervalent iodine agents enable diverse aliphatic C–H functionalization

Nature Chemistry, Год журнала: 2025, Номер 17(3), С. 365 - 372

Опубликована: Фев. 24, 2025

Язык: Английский

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