Benzylic C–H Azidation Using the Zhdankin Reagent and a Copper Photoredox Catalyst

Rabet, Pauline T. G.; Fumagalli, Gabriele; Boyd, Scott; Greaney, Michael F.

doi:10.1021/acs.orglett.6b00512

Cited by 133 publications

(79 citation statements)

References 41 publications

(28 reference statements)

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“…48 In addition to these methods, azides have been prepared by reactions at C–H bonds that are catalyzed by manganese–porphyrin complexes, that are photoinduced or promoted by visible light, or that are conducted with an oxidant such as K 2 S 2 O 8 . 25,49−54 Although diverse methods have been reported, the functionalization of natural products and complex pharmaceutical ingredients by these reactions has been limited to examples containing a minimum of functional groups.…”

Section: Introductionmentioning

confidence: 99%

Late Stage Azidation of Complex Molecules

2016

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Selective functionalization of complex scaffolds is a promising approach to alter the pharmacological profiles of natural products and their derivatives. We report the site-selective azidation of benzylic and aliphatic C–H bonds in complex molecules catalyzed by the combination of Fe(OAc)2 and a PyBox ligand. The same system also catalyzes the trifluoromethyl azidation of olefins to form derivatives of natural products containing both fluorine atoms and azides. In general, both reactions tolerate a wide range of functional groups and occur with predictable regioselectivity. Azides obtained by functionalization of C–H and C=C bonds were converted to the corresponding amines, amides, and triazoles, thus providing a wide variety of nitrogen-containing complex molecules.

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Section: Introductionmentioning

confidence: 99%

Late Stage Azidation of Complex Molecules

2016

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“…Based on these results, our initial aim was to expand the scope of domino transformations to other hypervalent iodine reagents, in particular azidobenziodoxol(on)es (ABX) . Our choice of ABX was justified by the large number of applications and chemical modifications related to azides, such as reduction to amines or cycloaddition with alkynes and the recent success reported with this reagent for azide transfer reactions . Best results in the domino cyclization‐alkynylation reactions had been obtained with hexafluoroisopropanol‐derived reagent 6 .…”

Section: Resultsmentioning

confidence: 99%

Bench‐Stable Electrophilic Indole and Pyrrole Reagents: Serendipitous Discovery and Use in C–H Functionalization

Caramenti

Waser

2017

Helvetica Chimica Acta

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The development of reagents allowing the reversal of the standard reactivity (Umpolung) of small building blocks is an important field of research in chemistry, as it allows increasing the flexibility of organic synthesis. Indoles and pyrroles are ubiquitous heterocycles in natural products and drugs. They are usually functionalized making use of their high nucleophilicity. In contrast, only few methods are based on the use of electrophilic indole and pyrrole synthons, as the needed reagents are highly unstable or can be used only with a very narrow scope. Herein, we report the serendipitous discovery and first use in the C–H functionalization of arenes of IndoleBX and PyrroleBX, new thermally highly stable benziodoxol(on)e hypervalent iodine reagents. IndoleBX and PyrroleBX could be obtained in one step from the corresponding heterocycles and acetoxy benziodoxolone using a Lewis acid catalyst. The mild reactions conditions allowed the introduction of a broad range of functional groups, including ethers, halogens and boronic esters. The new reagents could then be used in the rhodium‐ and ruthenium‐catalyzed C–H heteroarylation of arene rings bearing heterocyclic or benzamide directing groups. Such transformations could not be realized using previously reported C–H functionalization procedures.

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“…Mit diesen Katalysatoren kçnnen Perhalogenalkane und a-Carbonylhalogenide (Schema 72, rechts), aber auch elektronenarme Benzylhalogenide [262] mit Alkenen gekuppelt werden (Schema 72, rechts). [264] Das unterschiedliche Verhalten von [265,266] [260,263] WiefürRu II oder Ir III diskutiert (Schema 82), kçnnten die Cu I -katalysierten, durch sichtbares Licht vermittelten ATRA-Prozesse sowohl einem Photoredoxzyklus als auch einem Radikalkettenmechanismus unterliegen.…”

Section: [2+ +2]-cycloadditionenunclassified

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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Benzylic C–H Azidation Using the Zhdankin Reagent and a Copper Photoredox Catalyst

Cited by 133 publications

References 41 publications

Late Stage Azidation of Complex Molecules

Late Stage Azidation of Complex Molecules

Bench‐Stable Electrophilic Indole and Pyrrole Reagents: Serendipitous Discovery and Use in C–H Functionalization

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

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