Recent advances in the chemistry and applications of N-heterocyclic carbenes

Nature Reviews Chemistry, Год журнала: 2021, Номер 5(10), С. 711 - 725

Опубликована: Сен. 3, 2021

Язык: Английский

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Photocatalytic Late-Stage C–H Functionalization

Chemical Reviews, Год журнала: 2023, Номер 123(8), С. 4237 - 4352

Опубликована: Янв. 24, 2023

The emergence of modern photocatalysis, characterized by mildness and selectivity, has significantly spurred innovative late-stage C–H functionalization approaches that make use low energy photons as a controllable source. Compared to traditional strategies, photocatalysis paves the way toward complementary and/or previously unattainable regio- chemoselectivities. Merging compelling benefits with workflow offers potentially unmatched arsenal tackle drug development campaigns beyond. This Review highlights photocatalytic strategies small-molecule drugs, agrochemicals, natural products, classified according targeted bond newly formed one. Emphasis is devoted identifying, describing, comparing main mechanistic scenarios. draws critical comparison between established ionic chemistry photocatalyzed radical-based manifolds. aims establish current state-of-the-art illustrate key unsolved challenges be addressed in future. authors aim introduce general readership functionalization, specialist practitioners evaluation methodologies, potential for improvement, future uncharted directions.

Язык: Английский

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Energy transfer photocatalysis: exciting modes of reactivity

Chemical Society Reviews, Год журнала: 2024, Номер 53(3), С. 1068 - 1089

Опубликована: Янв. 1, 2024

Leveraging light energy to expose the ‘dark’ reactive states describes whole essence of triplet–triplet transfer. This offers an impressive opportunity conduct a multitude diverse reactions and access sought-after molecular motifs.

Язык: Английский

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Strain-Release Photocatalysis

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(38), С. 20716 - 20732

Опубликована: Сен. 15, 2023

The concept of strain in organic compounds is as old modern chemistry and was initially introduced to justify the synthetic setbacks along synthesis small ring systems (pars construens strain). In last decades, chemists have developed an arsenal strain-release reactions destruens strain) which can generate─with significant driving force─rigid aliphatic that act three-dimensional alternatives (hetero)arenes. Photocatalysis added additional dimension processes by leveraging energy photons create chemical complexity under mild conditions. This perspective presents latest advancements photocatalysis─with emphases on mechanisms, catalytic cycles, current limitations─the unique architectures be produced, possible future directions.

Язык: Английский

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Photochemical single-step synthesis of β-amino acid derivatives from alkenes and (hetero)arenes

Nature Chemistry, Год журнала: 2022, Номер 14(10), С. 1174 - 1184

Опубликована: Авг. 1, 2022

Язык: Английский

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Synthesis of Polysubstituted 2-Oxabicyclo[2.1.1]hexanes via Visible-Light-Induced Energy Transfer

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(44), С. 20207 - 20213

Опубликована: Окт. 27, 2022

Synthesis of bicyclic scaffolds has attracted growing interest because they are high importance in modern pharmaceutical development. Here we report a strategy to access polysubstituted 2-oxabicyclo[2.1.1]hexanes single operation from readily accessible benzoylformate esters and bicyclo[1.1.0]butanes via visible-light-induced triplet energy transfer catalysis. The process is proposed involve formal [2π + 2σ] photocycloaddition/backbone C-H abstraction/aryl group migration sequence. A diverse range (hetero)aryl groups successfully underwent the backbone (C2) position provide previously inaccessible molecules, ester product can serve as handle for downstream manipulation, thus offering opportunities rapidly build up molecular complexity new sp3-rich chemical space.

Язык: Английский

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Aroyl Fluorides as Bifunctional Reagents for Dearomatizing Fluoroaroylation of Benzofurans

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(16), С. 7072 - 7079

Опубликована: Март 22, 2022

The 2,3-dihydrobenzofuran scaffold is widely found in natural products and biologically active compounds. Herein, dearomatizing 2,3-fluoroaroylation of benzofurans with aroyl fluorides as bifunctional reagents to access 2,3-difunctionalized dihydrobenzofurans reported. reaction that occurs by cooperative NHC/photoredox catalysis provides 3-aroyl-2-fluoro-2,3-dihydrobenzofurans moderate good yield high diastereoselectivity. Cascades proceed via radical/radical cross-coupling a benzofuran radical cation generated the photoredox cycle neutral ketyl formed through NHC cycle. redox-neutral transformation exhibits broad substrate scope functional group compatibility. With anhydrides reagents, aroyloxyacylation achieved strategy can also be applied

Язык: Английский

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Catalytic Formal [2π+2σ] Cycloaddition of Aldehydes with Bicyclobutanes: Expedient Access to Polysubstituted 2‐Oxabicyclo[2.1.1]hexanes

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(34)

Опубликована: Июнь 12, 2023

Synthesis of bicyclic scaffolds has attracted tremendous attention because they are playing an important role as saturated bioisosteres benzenoids in modern drug discovery. Here, we report a BF3 -catalyzed [2π+2σ] cycloaddition aldehydes with bicyclo[1.1.0]butanes (BCBs) to access polysubstituted 2-oxabicyclo[2.1.1]hexanes. A new kind BCB containing acyl pyrazole group was invented, which not only significantly facilitates the reactions, but can also serve handle for diverse downstream transformations. Furthermore, aryl and vinyl epoxides be utilized substrates undergo BCBs after situ rearrangement aldehydes. We anticipate that our results will promote challenging sp3 -rich frameworks exploration BCB-based chemistry.

Язык: Английский

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N-Functionalized Pyridinium Salts: A New Chapter for Site-Selective Pyridine C–H Functionalization via Radical-Based Processes under Visible Light Irradiation

Accounts of Chemical Research, Год журнала: 2022, Номер 55(20), С. 3043 - 3056

Опубликована: Сен. 27, 2022

ConspectusThe radical-mediated C–H functionalization of pyridines has attracted considerable attention as a powerful tool in synthetic chemistry for the direct bonds pyridine scaffold. Classically, methods functionalized often involve Minisci-type reactions under strongly acidic conditions. However, site-selective unbiased systems been long-standing challenge because scaffold contains multiple competing reaction sites (C2 vs C4) to intercept free radicals. Therefore, prefunctionalization is required avoid issues observed with formation mixture regioisomers and overalkylated side products.Recently, N-functionalized pyridinium salts have attracting organic promising radical precursors surrogates. The notable advantage lies their ability enhance reactivity selectivity synthetically useful acid-free This approach enables exquisite regiocontrol nonclassical at C2 C4 positions mild conditions, which are suitable late-stage bioactive molecules greater complexity diversity. Over past five years, variety fascinating applications developed using various types visible light In addition, new platform alkene difunctionalization appropriately designed N-substituted bifunctional reagents reported, offering an innovative assembly process complex architectures. Intriguingly, strategies involving light-absorbing electron donor–acceptor (EDA) complexes between electron-rich donors further open up photocatalyst-free Furthermore, we enantioselective afford enantioenriched bearing through single-electron N-heterocyclic carbene (NHC) catalysis.Herein, provide broad overview our recent contributions development summarize cornerstones that successfully employ these major advances field systematically categorized on basis pyridines' N-substituent, N–X (X = O, N, C, SO2CF3), its patterns. identification activation modes mechanistic aspects discussed by providing representative each paradigm. We hope this Account will inspire interest continued innovation exploration transformations.

Язык: Английский

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EnT-Mediated N–S Bond Homolysis of a Bifunctional Reagent Leading to Aliphatic Sulfonyl Fluorides

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(4), С. 2364 - 2374

Опубликована: Янв. 18, 2023

Sulfur(VI) fluoride exchange (SuFEx) gives rise to a plethora of high-valent sulfur linkages; however, the availability (aliphatic) sulfonyl manifolds lag behind, owing limited sources introducing SO2F moiety via classical two-electron approach. Recently, radical-based methodologies have emerged as complementary strategy increase diversity accessible click partners. In this work, synthesis bench-stable sulfamoyl reagent is presented, which may undergo sigma-bond homolysis upon visible-light-induced sensitization form protected β-amino fluorides from alkene feedstocks. Notably, offers an appealing access various building blocks for peptido fluorides, relevant in medicinal chemistry context, well intriguing entry β-ammonium sulfonates and β-sultams, alkenes. Densely functionalized 1,3-sultones were obtained by employing allyl alcohols substrates. Surprisingly, chloride-derived β-imino underwent S-O bond formation ring closure yield rigid cyclopropyl sulfonate ester under SuFEx conditions. Furthermore, engaging thiol-based hydrogen atom donor reaction, reactivity same can be tuned toward direct aliphatic fluorides. Mechanistic experiments indicate energy transfer (EnT)-mediated process. The transient radical adds product occurs either radical-radical coupling or (HAT), respectively.

Язык: Английский

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