Application of Visible‐to‐UV Photon Upconversion to Photoredox Catalysis: The Activation of Aryl Bromides

Májek, Michal; Faltermeier, Uwe; Dick, Bernhard; Pérez‐Ruiz, Raúl; Wangelin, Axel Jacobi von

doi:10.1002/chem.201502698

Cited by 138 publications

(147 citation statements)

References 64 publications

(42 reference statements)

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“…For the formation of the radical anion and the semiquinone anion of Aq-OH upon photoirradiation in the presence of Et 3 N, see Figure 3. visioned that anthraquinone derivatives could be employed for the photoredox catalytic reduction of aryl halide substrates, including aryl chlorides, to obtain aryl radicals either for metalfree dehalogenation reactions [12,[32][33][34][35] or for synthetically important carbon-carbon [12,32,[36][37][38] bond-formation reactions. Such photoredox catalytic methods [12,13,[32][33][34][35][36][37][38][39] are valuable alternatives to well-established transition-metal-based activation methods. Herein, we report the use of 1,8-dihydroxyanthraquinone as a photocatalyst for synthetically important C-C bond-formation reactions with aryl halides as bench-stable starting materials and visible-light irradiation.…”

Section: Introductionmentioning

confidence: 99%

Anthraquinones as Photoredox Catalysts for the Reductive Activation of Aryl Halides

et al. 2017

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Quinones are ubiquitous in nature as structural motifs in natural products and redox mediators in biological electron-transfer processes. Although their oxidation properties have already been used widely in chemical and photochemical reactions, the applications of quinones in reductive photoredox catalysis are less explored. We report the visible-light photoreduction of aryl halides (Ar-X; X = Cl, Br, I) by 1,8-dihydroxyanthraquinone. The resulting aryl radical anions fragment into halide anions and aryl radicals, which react through hydrogen

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Section: Introductionmentioning

confidence: 99%

Anthraquinones as Photoredox Catalysts for the Reductive Activation of Aryl Halides

et al. 2017

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“…[14][15][16][17][18][19][20] Photoredox catalysis hinges on ap hotoinduced electron transfer between al ight-absorbing catalyst and as ubstrate;f or the latter, this redox activation unlocks the door to the realm of radical-ion chemistry;a nd the cycle is completed by catalyst regeneration through at hermal electron transfer involving as ubstrate-derived intermediate or as acrificial additive.R egarded from the storage perspective,the photon energy is distributed between ac atalyst-based and as ubstrate-based radical, which must normally recombine by asecond-order reaction. [2,23] Thec atalyst of this work is the popular ruthenium-trisbipyridyl ion [Ru(bpy) 3 ] 2+ . Hence,photoredox catalysis is inherently well-suited for accommodating photon pooling as an accessory; [3,21,22] and it is expected to perform this function better than two-photon processes without intervening electron transfer, [1] even when they are catalytic.…”

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confidence: 99%

Generating Hydrated Electrons for Chemical Syntheses by Using a Green Light‐Emitting Diode (LED)

2018

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We present the first working system for accessing and utilizing laboratory-scale concentrations of hydrated electrons by photoredox catalysis with a green light-emitting diode (LED). Decisive are micellar compartmentalization and photon pooling in an intermediate that decays with second-order kinetics. The only consumable is the nontoxic and bioavailable vitamin C. A turnover number of 1380 shows the LED method to be on par with electron generation by high-power pulsed lasers, but at a fraction of the cost. The extreme reducing power of the electron and its long unquenched life as a ground-state species are synergistic. We demonstrate the applicability to the dechlorination, defluorination, and hydrogenation of compounds that are inert towards all other visible-light photoredox catalysts known to date. A comprehensive mechanistic investigation from microseconds to hours yields results of general validity for photoredox catalysis with photon pooling, allowing optimization and upscaling.

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“…[65,66] Besser zu handhaben als die schwer lçslichen Perylenbisimide ist Rhodamin 6G 75 (Schema 21). Aryliodide,-bromide und -chloride 68 kçnnen durch dieses Verfahren in mäßigen bis ausgezeichneten Ausbeuten reduziert werden (Schema 20 a).…”

Section: )-C(sp 3 )-Bindungunclassified

Photokatalyse mit sichtbarem Licht: Welche Bedeutung hat sie für die organische Synthese?

et al. 2018

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Die Photokatalyse mit sichtbarem Licht hat sich im letzten Jahrzehnt zu einer breit angewandten Methode in der organischen Synthese entwickelt. Für viele wichtige Reaktionen, wie Kreuzkupplungen, α‐Amino‐Funktionalisierungen, Cycloadditionen, ATRA‐Reaktionen oder Fluorierungen, wurden photokatalytische Varianten berichtet. Um Chemiker bei der Auswahl photokatalytischer Methoden für ihre Synthesen zu unterstützen, vergleichen wir in diesem Aufsatz klassische und photokatalytische Verfahren für ausgewählte Reaktionsklassen und zeigen deren Vorteile und Grenzen auf. In vielen Fällen verlaufen die photokatalytischen Reaktionen unter milderen Reaktionsbedingungen, typischerweise bei Raumtemperatur, und stöchiometrische Reagenzien werden durch einfache Oxidanzien oder Reduktionsmittel wie Luft, Sauerstoff oder Amine ersetzt. Beeinflusst die Photokatalyse mit sichtbarem Licht die organische Synthese? Die Aussicht, Elektronen zu Substraten und Zwischenprodukten hin‐ und herzuschieben oder Energie selektiv durch einen sichtbares Licht absorbierenden Photokatalysatoren zu übertragen, verspricht die aktuellen Verfahren in der Radikalchemie zu verbessern und neue Wege durch den Zugang zu reaktiven, bisher unbekannten Spezies zu erschließen, insbesondere durch das Zusammenspiel von Photokatalyse mit der Organo‐ oder Metallkatalyse.

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Application of Visible‐to‐UV Photon Upconversion to Photoredox Catalysis: The Activation of Aryl Bromides

Cited by 138 publications

References 64 publications

Anthraquinones as Photoredox Catalysts for the Reductive Activation of Aryl Halides

Anthraquinones as Photoredox Catalysts for the Reductive Activation of Aryl Halides

Generating Hydrated Electrons for Chemical Syntheses by Using a Green Light‐Emitting Diode (LED)

Photokatalyse mit sichtbarem Licht: Welche Bedeutung hat sie für die organische Synthese?

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