Energy transfer photocatalysis: exciting modes of reactivity

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(3), P. 1068 - 1089

Published: Jan. 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.

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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Metal-Free Amino(hetero)arylation and Aminosulfonylation of Alkenes Enabled by Photoinduced Energy Transfer

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(30), P. 16630 - 16641

Published: July 24, 2023

β-(Hetero)arylethylamines are privileged structural motifs found in many high-value organic molecules, including pharmaceuticals and natural products. To construct these important molecular skeletons, previous methods mainly achieved by amino(hetero)arylation reaction with the aid of transition metals preactivated substrates. Herein, we report a metal-free photoinduced intermolecular for single-step installation both (hetero)aryl iminyl groups across alkenes an efficient regioselective manner. This method shows broad scope (up to 124 examples) excellent tolerance various olefins─from simplest ethylene complex multisubstituted can all participate reaction. Furthermore, aminosulfonylation be also conducted presence sodium bisulfite as SO2 source.

Language: Английский

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γ-Amino Alcohols via Energy Transfer Enabled Brook Rearrangement

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(15), P. 10899 - 10907

Published: April 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.

Language: Английский

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Visible-Light-Induced Energy-Transfer-Mediated Hydrofunctionalization and Difunctionalization of Unsaturated Compounds via Sigma-Bond Homolysis of Energy-Transfer Acceptors

ACS Catalysis, Journal Year: 2025, Volume and Issue: 15(3), P. 1854 - 1941

Published: Jan. 17, 2025

Over the past decade, visible-light-mediated energy-transfer (EnT) catalysis, particularly triplet–triplet (TTEnT) has emerged as a mild and environmentally friendly approach for diverse organic synthetic transformations. In contrast to photoredox which typically requires sacrificial electron donors or acceptors complete catalytic cycle, EnT photocatalysis generally proceeds with high atom economy while minimizing generation of wasteful byproducts. Furthermore, successful catalysis is contingent upon precise control redox potentials both photocatalysts substrates, strategies are primarily influenced by triplet energy compatibility between these entities. Considering growing importance photocatalysis, well hydrofunctionalization difunctionalization reactions in synthesis, this review systematically summarizes significant advancements EnT-enabled unsaturated compounds via sigma-bond homolysis over decade. Special emphasis placed on elucidating substrate scopes mechanistic scenarios. Additionally, discusses versatile applications methodologies addresses current challenges opportunities within evolving research field. This structured into six main categories based different types sigma-bonds undergoing homolysis. These include transformations mediated 1) N–O bond oxime esters other N,O-radical precursors; 2) N–S N-sulfonyl imines N,S-radical 3) chalcogen–chalcogen disulfides oxy/thio/selenosulfonates; 4) C–S tri/difluoromethylated sulfinates, acetylenic triflones, arylsulfonium salts; 5) C–X (X = halogen) halides; 6) acceptors. Through providing theoretical backgrounds along comprehensive overview currently employed acceptors, photosensitizers, contemporary EnT-induced compounds, aims serve an invaluable resource future innovations rapidly

Language: Английский

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Photosensitized Imino-Thiocyanation of Alkenes

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 17, 2025

A metal-free photosensitized 1,2-imino-thiocyanation of olefins has been established by using the easily accessible bifunctional reagent S-cyano-N-(diphenylmethylene) thiohydroxylamine. wide range were successfully transformed into corresponding β-iminothiocyanates in moderate to high yields. This protocol stands out for its nature, broad substrate compatibility, and atom step economy, providing an effective strategy assembling β-amino thiocyanate-containing scaffolds.

Language: Английский

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Imidazophenothiazine-Based Thermally Activated Delayed Fluorescence Materials with Ultra-Long-Lived Excited States for Energy Transfer Photocatalysis

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(33), P. 18366 - 18381

Published: Aug. 9, 2023

Triplet-triplet energy transfer (EnT) is a powerful activation pathway in photocatalysis that unlocks new organic transformations and improves the sustainability of synthesis. Many current examples, however, still rely on platinum-group metal complexes as photosensitizers, with associated high costs environmental impacts. Photosensitizers exhibit thermally activated delayed fluorescence (TADF) are attractive fully alternatives EnT photocatalysis. However, TADF photocatalysts incorporating heavy atoms remain rare, despite their utility inducing efficient spin-orbit-coupling, intersystem-crossing, consequently triplet population. Here, we describe synthesis imidazo-phenothiazine (IPTZ), sulfur-containing heterocycle locked planar structure shallow LUMO level. This acceptor used to prepare seven TADF-active energies up 63.9 kcal mol-1. We show sulfur incorporation spin-orbit coupling increases lifetimes 3.64 ms, while also allowing for tuning photophysical properties via oxidation at atom. These IPTZ materials applied five seminal reactions: [2 + 2] cycloaddition, disulfide-ene reaction, Ni-mediated C-O C-N cross-coupling afford etherification, esterification, amination products, outcompeting industry-standard photocatalyst 2CzPN four studied scenarios. Detailed theoretical studies understand structure-activity relationships demonstrate key role atom effect design superior photocatalytic performance.

Language: Английский

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Regiospecific Alkene Aminofunctionalization via an Electrogenerated Dielectrophile

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(15), P. 8299 - 8307

Published: April 6, 2023

Modular strategies to rapidly increase molecular complexity have proven immensely synthetically valuable. In principle, transformation of an alkene into a dielectrophile presents opportunity deliver two unique nucleophiles across alkene. Unfortunately, the selectivity profiles known dielectrophiles largely precluded this deceptively simple synthetic approach. Herein, we demonstrate that dicationic adducts generated through electrolysis alkenes and thianthrene possess profile relative more conventional dielectrophiles. Specifically, these species undergo single perfectly regioselective substitution reaction with phthalimide salts. This observation unlocks appealing new platform for aminofunctionalization reactions. As illustrative example, implement reactivity paradigm address longstanding challenge: diamination distinct nitrogen nucleophiles. Studies mechanism process reveal key alkenyl thianthrenium salt intermediate controls exquisite regioselectivity highlight importance proton sources in controlling sulfonium electrophiles.

Language: Английский

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Photocatalytic 1,2-Iminosulfonylation and Remote 1,6-Iminosulfonylation of Olefins

Organic Letters, Journal Year: 2023, Volume and Issue: 25(10), P. 1742 - 1747

Published: March 8, 2023

A new class of iminosulfonylation reagents were developed and extensively used in the 1,2-iminosulfonylation various olefins. Olefins containing bioactive molecules, such as indomethacin, gemfibrozil, clofibrate, fenbufen, afforded desired products synthetically useful yields. Furthermore, first remote 1,6-iminosulfonylation alkenes was realized by using oxime ester bifunctionalization reagents. Overall, more than 40 structurally diverse β-imine sulfones obtained moderate to excellent

Language: Английский

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Photoinduced difunctionalization with bifunctional reagents containing N-heteroaryl moieties

Science China Chemistry, Journal Year: 2023, Volume and Issue: 66(6), P. 1688 - 1700

Published: May 10, 2023

Language: Английский

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