N–O Bond Activation by Energy Transfer Photocatalysis

Accounts of Chemical Research, Journal Year: 2022, Volume and Issue: 55(17), P. 2526 - 2541

Published: Aug. 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.

Language: 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, Journal Year: 2023, Volume and Issue: 145(4), P. 2364 - 2374

Published: Jan. 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.

Language: Английский

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Advances in the construction of diverse SuFEx linkers

National Science Review, Journal Year: 2023, Volume and Issue: 10(6)

Published: April 29, 2023

Abstract Sulfur fluoride exchange (SuFEx), a new generation of click chemistry, was first presented by Sharpless, Dong and co-workers in 2014. Owing to the high stability yet efficient reactivity SVI–F bond, SuFEx has found widespread applications organic synthesis, materials science, chemical biology drug discovery. A diverse collection linkers emerged, involving gaseous SO2F2 SOF4 hubs; SOF4-derived iminosulfur oxydifluorides; O-, N- C-attached sulfonyl fluorides sulfonimidoyl fluorides; novel sulfondiimidoyl fluorides. This review summarizes progress these connectors, with an emphasis on analysing advantages disadvantages synthetic strategies connectors based concept, it is expected be beneficial researchers rapidly correctly understand this field, thus inspiring further development chemistry.

Language: Английский

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Radical approaches to C–S bonds

Nature Reviews Chemistry, Journal Year: 2023, Volume and Issue: 7(8), P. 573 - 589

Published: June 21, 2023

Language: Английский

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Sulfur(vi) fluorides as tools in biomolecular and medicinal chemistry

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(7), P. 1356 - 1372

Published: Jan. 1, 2023

This review highlights key advances in the synthesis and biomolecular applications of sulfur( vi )-fluorides.

Language: Английский

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Radical Hydro‐Fluorosulfonylation of Unactivated Alkenes and Alkynes

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(39)

Published: Aug. 9, 2022

Abstract Recently, radical fluorosulfonylation is emerging as an appealing approach for the synthesis of sulfonyl fluorides, which are highly in demand various disciplines, particularly chemical biology and drug discovery. Here, we report first establishment hydro‐fluorosulfonylation alkenes, enabled by using 1‐fluorosulfonyl 2‐aryl benzoimidazolium (FABI) effective redox‐active precursor. This method provides a new facile aliphatic fluorides from unactivated can be further applied to late‐stage modifications natural products peptides, well ligation drugs combination with click chemistry. Remarkably, this system could enable alkynes, affording valuable alkenylsulfonyl fluoride rare, high Z ‐selectivity, normally less stable more challenging synthesize comparison E ‐configured products.

Language: Английский

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Photocatalytic Sulfonyl Fluorination of Alkyl Organoboron Substrates

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(6), P. 3668 - 3675

Published: Feb. 28, 2023

Sulfonyl fluorides are highly versatile molecules for click chemistry that have found applications in many areas of and biology. Recent chemical approaches focused on the synthesis alkyl sulfonyl from readily available starting materials. Here, we report a photocatalytic organotrifluoroborates boronic acid pinacol esters, which building blocks commonly employed by medicinal chemists bioactive molecules. Steady-state time-resolved spectroscopy confirmed absorption photons acridinium catalysts leads to oxidation organotrifluoroborate substrates. The reaction exhibits broad functional group tolerance, can be attributed mild activation with visible light. Importantly, this general approach provides easy access primary, secondary, tertiary fluorides.

Language: Английский

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Decarboxylative Sulfonylation of Carboxylic Acids under Mild Photomediated Iron Catalysis

Organic Letters, Journal Year: 2024, Volume and Issue: 26(12), P. 2381 - 2386

Published: March 15, 2024

Organic sulfones are an important class of chemical compounds widely used in many research fields. The direct decarboxylative sulfonylation carboxylic acids is attractive but challenging, particularly when iron as a metal catalyst. Herein, we describe photoinduced iron-catalytic method for the synthesis directly using via radical-based decarboxylation. This protocol mild, highly efficient, and easy-to-operate. A broad scope carbon electrophiles could be well tolerated. mechanism involving iron-catalyzed decarboxylation, radical transfer, single-electron reduction, nucleophilic attack proposed.

Language: Английский

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Visible-Light-Induced Decarboxylative Aminosulfonylation of (Hetero)aryl Carboxylic Oxime Esters

Organic Letters, Journal Year: 2024, Volume and Issue: 26(3), P. 713 - 718

Published: Jan. 12, 2024

Sulfonamides are important structures in pharmaceuticals, agrochemicals, and organocatalysts, yet the rapid benign synthesis of these compounds is still a great challenge. Herein we report photoinduced method for synthesizing sulfonamides from (hetero)aryl carboxylic acid oxime esters. This reaction proceeds via one-pot cascade radical–radical cross-coupling by energy-transfer-mediated photocatalysis. A wide substrate scope including substrates late-stage modification pharmaceutical molecular entities reveal its generality.

Language: Английский

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Copper-Catalyzed Chemoselective (Amino)fluorosulfonylation of Hydrocarbons via Intramolecular Fluorine-Atom Transfer

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(6), P. 4318 - 4328

Published: March 6, 2024

Sulfonyl fluorides have found increasing applications as functional molecules in chemistry and biology. We herein report a copper-catalyzed atom-economical access to two categories of sulfonyl through radical relay strategy the presence an SO2 surrogate. The aliphatic C(sp3)–H bond N-fluoro-N-alkyl sulfonamides reacted via 1,5-hydrogen atom transfer (HAT) process, affording alkanesulfonyl with proximal amino group. On other hand, utilizing substrates containing proper C═C double resulted intramolecular olefin aminofluorosulfonylation, allowing synthesis fluorosulfonyl-functionalized pyrrolidines piperidines atom-transfer addition (ATRA). Both reaction systems proceeded under mild conditions, requiring no additional fluorine source. Experimental computational studies suggest that S–F coupling is likely achieved radical-rebound pathway. By taking advantage SuFEx multifunctionality products, method applicable late-stage modification bioactive compounds, drug ligation chemistry, organic synthesis.

Language: Английский

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