Photons or Electrons? A Critical Comparison of Electrochemistry and Photoredox Catalysis for Organic Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2487 - 2649

Опубликована: Ноя. 9, 2021

Redox processes are at the heart of synthetic methods that rely on either electrochemistry or photoredox catalysis, but how do and catalysis compare? Both approaches provide access to high energy intermediates (e.g., radicals) enable bond formations not constrained by rules ionic 2 electron (e) mechanisms. Instead, they 1e mechanisms capable bypassing electronic steric limitations protecting group requirements, thus enabling chemists disconnect molecules in new different ways. However, while providing similar intermediates, differ several physical chemistry principles. Understanding those differences can be key designing transformations forging disconnections. This review aims highlight these similarities between comparing their underlying principles describing impact electrochemical photochemical methods.

Язык: Английский

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Enantioselective radical C–H amination for the synthesis of β-amino alcohols

Nature Chemistry, Год журнала: 2020, Номер 12(8), С. 697 - 704

Опубликована: Июнь 22, 2020

Язык: Английский

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Switchable Divergent Synthesis Using Photocatalysis

ACS Catalysis, Год журнала: 2022, Номер 12(3), С. 1857 - 1878

Опубликована: Янв. 20, 2022

A highly selective and divergent synthesis enables access to various molecules has garnered broad interest from not only organic chemists but also medicinal biologists who work with chemical libraries. Since the 20th century, such transformations have been achieved using transition-metal-catalyzed reactions, in which choice of catalyst or ligand crucially affects selectivity. Over past several decades, photocatalysts attracted a considerable amount attention because they provide additional ways control reaction intermediates product selectivity via electron energy transfer. From this perspective, we highlight recent development switchable syntheses photocatalysts, are difficult achieve classical catalytic transformations.

Язык: Английский

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Recent development of the transition metal complexes showing strong absorption of visible light and long-lived triplet excited state: From molecular structure design to photophysical properties and applications

Coordination Chemistry Reviews, Год журнала: 2020, Номер 417, С. 213371 - 213371

Опубликована: Май 27, 2020

Язык: Английский

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Strongly Red-Emissive Molecular Ruby [Cr(bpmp)₂]³⁺ Surpasses [Ru(bpy)₃]²⁺

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(30), С. 11843 - 11855

Опубликована: Июль 23, 2021

Gaining chemical control over the thermodynamics and kinetics of photoexcited states is paramount to an efficient sustainable utilization photoactive transition metal complexes in a plethora technologies. In contrast energies charge transfer described by spatially separated orbitals, spin-flip cannot straightforwardly be predicted as Pauli repulsion nephelauxetic effect play key roles. Guided multireference quantum calculations, we report novel highly luminescent emitter with chemically blue-shifted luminescence. The emission band chromium complex [Cr(bpmp)2]3+ (bpmp = 2,6-bis(2-pyridylmethyl)pyridine) shifted higher energy from ca. 780 nm observed for known emissive chromium(III) 709 nm. photoluminescence yields climb 20%, very long excited state lifetimes millisecond range are achieved at room temperature acidic D2O solution. Partial ligand deuteration increases yield 25%. high its facile reduction [Cr(bpmp)2]2+ result redox potential. ligand's methylene bridge acts Brønsted acid quenching luminescence pH. Combined pH-insensitive emitter, ratiometric optical pH sensing single wavelength excitation. photophysical ground properties (quantum yield, lifetime, potential, acid/base) this incorporating earth-abundant surpass those classical precious [Ru(α-diimine)3]2+ complexes, which commonly employed photo(redox) catalysis, underlining bright future these molecular ruby analogues.

Язык: Английский

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Urea as a Redox-Active Directing Group under Asymmetric Photocatalysis of Iridium-Chiral Borate Ion Pairs

Journal of the American Chemical Society, Год журнала: 2020, Номер 142(46), С. 19462 - 19467

Опубликована: Ноя. 5, 2020

The development of a photoinduced, highly diastereo- and enantioselective [3 + 2]-cycloaddition N-cyclopropylurea with α-alkylstyrenes is reported. This asymmetric radical cycloaddition relies on the strategic placement urea cyclopropylamine as redox-active directing group (DG) anion-binding ability use an ion pair, comprising iridium polypyridyl complex weakly coordinating chiral borate ion, photocatalyst. structure anion component catalyst governs reactivity, pertinent structural modification enables high levels catalytic activity stereocontrol. system tolerates range hence offers rapid access to various aminocyclopentanes contiguous tertiary quaternary stereocenters, DG readily removable.

Язык: Английский

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Visible-Light-Induced Radical Carbo-Cyclization/gem-Diborylation through Triplet Energy Transfer between a Gold Catalyst and Aryl Iodides

Journal of the American Chemical Society, Год журнала: 2020, Номер 142(23), С. 10485 - 10493

Опубликована: Апрель 30, 2020

Geminal diboronates have attracted significant attention because of their unique structures and reactivity. However, benzofuran-, indole-, benzothiophene-based benzylic gem-diboronates, building blocks for biologically relevant compounds, are unknown. A promising protocol using visible light aryl iodides constructing valuable blocks, including via radical carbo-cyclization/gem-diborylation alkynes with a high functional group tolerance is presented. The utility these gem-diboronates has been demonstrated by 10 g scale conversion, versatile transformations, the synthesis approved drug scaffolds two drugs, even polymer synthesis. mechanistic investigation indicates that merging dinuclear gold catalyst (photoexcitation 315–400 nm UVA light) Na2CO3 directly responsible photosensitization 254 UV blue LED (410–490 nm, λmax = 465 nm) through an energy transfer (EnT) process, followed homolytic cleavage C–I bond in iodide substrates.

Язык: Английский

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Stereodivergent Synthesis of BothZ- andE-Alkenes by Photoinduced, Ni-Catalyzed Enantioselective C(sp³)–H Alkenylation

ACS Catalysis, Год журнала: 2021, Номер 11(21), С. 13567 - 13574

Опубликована: Окт. 25, 2021

The enantio- and stereoselective synthesis of stereodefined alkenes, especially the functionalized Z-isomer with an allylic stereogenic center, remains a great challenge. We herein report enantioselective benzylic C(sp3)–H alkenylation simple alkylarenes vinyl bromides via photoinduced nickel catalysis, which allows for stereodivergent both enantioenriched Z- E-alkenes bearing aryl-substituted, tertiary centers. Interestingly, tunable Z/E-selectivity is achieved by energy transfer catalysis judicious choice photocatalyst counteranion. This versatile strategy features starting materials, mild reaction conditions, broad substrate scope, divergent E-selectivity, high enantioselectivities. Moreover, formal asymmetric alkylation can also be one-pot alkenylation/reduction sequence, providing complementary to address notoriously challenging stereochemical control in C(sp3)–C(sp3) bond construction.

Язык: Английский

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Charge‐Transfer and Spin‐Flip States: Thriving as Complements

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(15)

Опубликована: Окт. 4, 2022

Abstract Transition metal complexes with photoactive charge‐transfer excited states are pervasive throughout the literature. In particular, [Ru(bpy) 3 ] 2+ (bpy=2,2′‐bipyridine), its metal‐to‐ligand emission, has been established as a key complex. Meanwhile, interest in so‐called spin‐flip metal‐centered risen dramatically after molecular ruby [Cr(ddpd) 2 3+ (ddpd= N , ′‐dimethyl‐ ′‐dipyridin‐2‐yl‐pyridine‐2,6‐diamine) led to design principles access strong, long‐lived emission from photostable chromium(III) complexes. This Review contrasts properties of emissive and by using prototypical examples. We discuss relevant states, tunability their energy lifetimes, response external stimuli. Finally, we identify strengths weaknesses applications such photocatalysis circularly polarized luminescence.

Язык: Английский

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Ion-pair reorganization regulates reactivity in photoredox catalysts

Nature Chemistry, Год журнала: 2022, Номер 14(7), С. 746 - 753

Опубликована: Апрель 14, 2022

Язык: Английский

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