A general electron donor–acceptor complex for photoactivation of arenes via thianthrenation

Chemical Science, Год журнала: 2022, Номер 13(19), С. 5659 - 5666

Опубликована: Янв. 1, 2022

General photoactivation of EDA complexes between arylsulfonium salts and 1,4-diazabicyclo[2.2.2]octane was discovered. This practical mode enables the generation aryl radicals for C–H functionalization arenes.

Язык: Английский

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Photochemical radical cyclization reactions with imines, hydrazones, oximes and related compounds

Chemical Society Reviews, Год журнала: 2021, Номер 50(13), С. 7418 - 7435

Опубликована: Янв. 1, 2021

Photochemical reactions of imines, hydrazones, oximes and related compounds provides an efficient access to radical intermediates in the synthesis heterocycles.

Язык: Английский

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Asymmetric three-component olefin dicarbofunctionalization enabled by photoredox and copper dual catalysis

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

Опубликована: Март 22, 2021

Abstract The intermolecular three-component alkene vicinal dicarbofunctionalization (DCF) reaction allows installation of two different carbon fragments. Despite extensive investigation into its ionic chemistry, the enantioseletive radical-mediated versions DCF reactions remain largely unexplored. Herein, we report an intermolecular, enantioselective radical olefins enabled by merger addition and cross-coupling using photoredox copper dual catalysis. Key to success this protocol relies on chemoselective acyl cyanoalkyl radicals, generated in situ from redox-active oxime esters a photocatalytic N-centered iminyl radical-triggered C-C bond cleavage event, onto alkenes form new radicals. Single electron metalation such newly formed radicals TMSCN-derived L1 Cu(II)(CN) 2 complex leads asymmetric cross-coupling. This process proceeds under mild conditions, tolerates diverse range functionalities synthetic handles, leading valuable optically active β –cyano ketones alkyldinitriles, respectively, highly manner (>60 examples, up 97% ee).

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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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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Recent advances in radical-mediated transformations of 1,3-dienes

CHINESE JOURNAL OF CATALYSIS (CHINESE VERSION), Год журнала: 2022, Номер 43(3), С. 548 - 557

Опубликована: Фев. 2, 2022

Язык: Английский

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Access to axially chiral styrenes via a photoinduced asymmetric radical reaction involving a sulfur dioxide insertion

Chem Catalysis, Год журнала: 2022, Номер 2(1), С. 164 - 177

Опубликована: Янв. 1, 2022

Язык: Английский

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Ligand Modification of Au₂₅ Nanoclusters for Near-Infrared Photocatalytic Oxidative Functionalization

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(9), С. 3787 - 3792

Опубликована: Фев. 28, 2022

The inorganic-organic interface between metal catalysts and their substrates greatly influences reaction processes, but few studies of this have been conducted for a detailed understanding its structure. Herein, we describe the synthesis structural determination an arylthiolated Au25(F-Ph)18- nanocluster characterize in detail key roles ligands photocatalyzed oxidative functionalization reactions. most significant findings are that (i) interactions established to avoid distortion geometric structure, limit Jahn-Teller effect, protect from oxidization (ii) low energy gap (HOMO-LUMO) synthetic clusters enables three types photocatalytic reactions by near-infrared light (850 nm).

Язык: Английский

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Energy-transfer-induced [3+2] cycloadditions of N–N pyridinium ylides

Nature Chemistry, Год журнала: 2023, Номер 15(8), С. 1091 - 1099

Опубликована: Июнь 26, 2023

Язык: Английский

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γ-Amino Alcohols via Energy Transfer Enabled Brook Rearrangement

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(15), С. 10899 - 10907

Опубликована: Апрель 3, 2024

In the long-standing quest to synthesize fundamental building blocks with key functional group motifs, photochemistry in recent past has comprehensively established its attractiveness. Amino alcohols are not only functionally diverse but ubiquitous biologically active realm of compounds. We developed bench-stable bifunctional reagents that could then access sparsely reported γ-amino directly from feedstock alkenes through energy transfer (EnT) photocatalysis. A designed 1,3-linkage across is made possible by intervention a radical Brook rearrangement takes place downstream EnT-mediated homolysis our reagent(s). combination experimental mechanistic investigations and detailed computational studies (DFT) indicates chain propagated reaction pathway.

Язык: Английский

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