Catalysis in the Excited State: Bringing Innate Transition Metal Photochemistry into Play

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 4665 - 4680

Published: March 5, 2025

Transition metal catalysis is an indispensable tool for organic synthesis that has been harnessed, modulated, and perfected many decades by careful selection of centers ligands, giving rise to synthetic methods with unparalleled efficiency chemoselectivity. Recent developments have demonstrated how light irradiation can also be recruited as a powerful dramatically alter the outcome catalytic reactions, providing access innovative pathways remarkable potential. In this context, adoption photochemical conditions mainstream strategy drive reactions unveiled exciting opportunities exploit rich excited-state framework transition metals applications. This Perspective examines advances in application complexes standalone photocatalysts, exploiting innate reactivity their excited states beyond common use photoredox catalysts. An account relevant examples dissected provide discussion on electronic reorganization, orbitals involved, associated different types states. analysis aims practitioners fundamental principles guiding strategies understand, design, apply light-activation homogeneous synthesis.

Language: Английский

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Energy‐Transfer Enabled 1,4‐Aryl Migration

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 5, 2024

Abstract Functional group translocation is undoubtedly a pivotal synthetic transformation in organic chemistry. Numerous types of reactions involving radical 1,2‐aryl or 1,4‐aryl migration via electron transfer mechanism have been extensively investigated. Nevertheless, energy‐transfer enabled 1,4‐arylation remains unknown. Herein we disclose that an unprecedented di‐π‐ethane rearrangement featuring facilitated by energy catalysis under visible light conditions. The newly developed mild protocol exhibits tolerance towards diverse functional groups and enables the multitude aromatic rings, encompassing both electron‐withdrawing electron‐rich groups. open‐shell strategy has also found successful application modification several drugs. Large‐scale experiments, continuous‐flow experiment, versatile manipulation products demonstrated robustness potential utility this method. Preliminary mechanistic studies supported involvement species provided evidence for mechanism.

Language: Английский

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C3 Selective Hydroxylation of Pyridines via Photochemical Valence Isomerization of Pyridine N-Oxides

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(35), P. 24257 - 24264

Published: Aug. 22, 2024

The C–H hydroxylation of the pyridine C3 position is a highly desirable transformation but remains great challenge due to inherent electronic properties this heterocycle core which bring difficulties in chemical reactivity and regioselectivity. Herein we present an efficient method for formal selective pyridines via photochemical valence isomerization N-oxides. This metal-free features operational simplicity compatibility with diverse array functional groups, resulting hydroxylated products are amenable further elaboration synthetically useful building blocks. synthetic utility strategy demonstrated effective late-stage functionalization pyridine-containing medicinally relevant molecules versatile derivatizations 3-pyridinols.

Language: Английский

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Activity Rationalization and Mechanism Tracking of CO2 Photoreduction over 2D-based Layered-Bismuth-Oxyhalides

EnergyChem, Journal Year: 2025, Volume and Issue: unknown, P. 100143 - 100143

Published: Jan. 1, 2025

Language: Английский

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Real‐Time In Situ Raman Monitoring of Photomechanochemical Reactions

Chemistry - Methods, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 31, 2025

Abstract In its ongoing development, mechanochemistry is becoming equipped with additional energy inputs such as light. this work we demonstrate a proof‐of‐principle setup for real‐time in situ Raman monitoring of photomechanochemical reactions. Using photoisomerization azobenzenes, and photolysis adamantane diazirine model reactions, show that multiple cycles can be performed monitored ball mill, highlight reaction selectivity achieved by photomechanochemistry.

Language: Английский

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Ti Coating-Enhanced Tribocatalytic Degradation of Organic Dyes by CdS Nanoparticles

Inorganics, Journal Year: 2025, Volume and Issue: 13(2), P. 46 - 46

Published: Feb. 6, 2025

Coating disk-shaped materials on the bottoms of containers has become a highly effective method for tribocatalysis enhancement. Here, effects Ti coatings tribocatalytic degradation organic dyes by CdS nanoparticles were systematically studied. For both 50 mg/L rhodamine B (RhB) and 20 methyl orange (MO) solutions, was dramatically enhanced in Ti-coated beakers compared to as-received glass-bottomed beakers, with rate constant increased 4.77 5.21 times, respectively. Moreover, MO using CdS, two quite different modes identified between Al2O3 coatings. Electron paramagnetic resonance (EPR) spectroscopy analyses showed that more radicals generated when rubbed against coating than glass bottom, boron nitride employed verify enhancement associated resulted from interactions CdS. These findings underscore importance catalyst material selection systems, offering valuable insights development efficient environmental purification technologies.

Language: Английский

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Photoenolization of α,β-Unsaturated Esters Enables Enantioselective Contra-Thermodynamic Positional Isomerization to α-Tertiary β,γ-Alkenyl Esters

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: 147(9), P. 7452 - 7460

Published: Feb. 24, 2025

The enantioselective protonation of prochiral enolates is an ideal and straightforward platform to synthesize stereodefined α-tertiary esters, which are recurring motifs in a myriad biorelevant molecules important intermediates thereof. However, this approach remains onerous, particularly when dealing with α-unactivated esters related acids, as enantioinduction on the nascent nucleophile necessitates peremptory reaction conditions, thus far only achieved via preformed enolates. A complementary contra-thermodynamic catalytic strategy herein described, where transient photoenol, form ketene hemiacetal, enantioselectively protonated chiral phosphoric acid (CPA). photoketene hemiacetals procured from excited α,β-unsaturated specifically Z-geometric isomer through [1,5]-hydride shift chemically productive nonradiative relaxation pathway. Tautomerization formal 1,3-proton transfer hemiacetal CPA proton shuttle delivers α-branched β,γ-alkenyl good excellent yields enantioselectivity under mild conditions. Furthermore, current protocol was coupled functional group interconversion experiments, well total synthesis known marine γ-butyrolactone-type metabolite. Performing continuous photoflow setup also enabled gram-scale ester up 92% ee.

Language: Английский

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Tandem design on electrocatalysts and reactors for electrochemical CO2 reduction

CHINESE JOURNAL OF CATALYSIS (CHINESE VERSION), Journal Year: 2025, Volume and Issue: 69, P. 1 - 16

Published: Feb. 1, 2025

Language: Английский

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Arylthianthrenium Salts for Triplet Energy Transfer Catalysis

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(44), P. 30474 - 30482

Published: Oct. 28, 2024

Sigma bond cleavage through electronically excited states allows synthetically useful transformations with two radical species. Direct excitation of simple aryl halides to form both and halogen radicals necessitates UV-C light, so undesired side reactions are often observed specific equipment is required. Moreover, only extended π systems comparatively low triplet energy applicable transfer catalysis. Here we show the conceptual advantages arylthianthrenium salts (ArTTs) for catalysis high efficiency compared conventional (pseudo)halides their utility in arylation ethylene. The fundamental advance enabled by ArTTs that may originate large part from electronic interplay between distinct sulfur atoms tricyclic thianthrene scaffold, which not accessible either or other sulfonium salts.

Language: Английский

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Photochemical Deracemization of Lactams with Deuteration Enabled by Dual Hydrogen Atom Transfer

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 18, 2024

Photochemical deracemization has emerged as one of the most straightforward approaches to access highly enantioenriched compounds in recent years. While excited-state events such energy transfer, single electron and ligand-to-metal charge transfer have been leveraged promote stereoablation, relying on hydrogen atom which circumvent limitations imposed by triplet redox potential racemic substrates, remain underexplored. Conceptually, attractive method for tertiary stereocenter might be abstraction followed donation. However, implementing a strategy poses significant challenges, primarily because products are also reactive if chiral catalyst is unable differentiate between two enantiomers. Herein we report distinct dual photochemical δ- γ-lactams, achieving high enantioenrichment deuterium incorporation despite inherent reactivity products. Mechanistic studies reveal that benzophenone enables nonselective while tetrapeptide-derived thiol dictates enantioselectivity donation step. More importantly, pyridine-based alcohol was found play crucial roles facilitating well enhancing

Language: Английский

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