Transition‐Metal‐Free Synthesis of Phenanthridinones through Visible‐Light‐Driven Oxidative C–H Amidation

Usami, Kaoru; Yamaguchi, Eiji; Tada, Norio; Itoh, Akichika

doi:10.1002/ejoc.201900536

Cited by 20 publications

(9 citation statements)

References 34 publications

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“…Itoh and co-workers in 2020 disclosed an organo-photocatalytic method enabling intramolecular arene C(sp 2 )–H bond amidation through amidyl radical generation and subsequent cyclization ( Scheme 34 ). 173 The combination of 1-chloroanthraquinone ( 1-Cl-AQN ) photocatalyst and K 2 CO 3 Brønsted base, under an air atmosphere in CHCl 3 solution under visible-light irradiation gave access to 17 phenanthridinone products, in yields of 69–99%. The reaction proceeded at ambient temperature and tolerated greater variation in the electronic properties of the amide N -aryl group than the method of Hong, including halogenation ( 34.3 ) and a benzothiazole ( 34.4 ).…”

Section: N -Centered Radical Generation From N–h Bonds Through Photochemical and Electrochemical Pcet Processesmentioning

confidence: 99%

Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis

et al. 2021

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We present here a review of the photochemical and electrochemical applications of multi-site proton-coupled electron transfer (MS-PCET) in organic synthesis. MS-PCETs are redox mechanisms in which both an electron and a proton are exchanged together, often in a concerted elementary step. As such, MS-PCET can function as a non-classical mechanism for homolytic bond activation, providing opportunities to generate synthetically useful free radical intermediates directly from a wide variety of common organic functional groups. We present an introduction to MS-PCET and a practitioner’s guide to reaction design, with an emphasis on the unique energetic and selectivity features that are characteristic of this reaction class. We then present chapters on oxidative N–H, O–H, S–H, and C–H bond homolysis methods, for the generation of the corresponding neutral radical species. Then, chapters for reductive PCET activations involving carbonyl, imine, other X=Y π-systems, and heteroarenes, where neutral ketyl, α-amino, and heteroarene-derived radicals can be generated. Finally, we present chapters on the applications of MS-PCET in asymmetric catalysis and in materials and device applications. Within each chapter, we subdivide by the functional group undergoing homolysis, and thereafter by the type of transformation being promoted. Methods published prior to the end of December 2020 are presented.

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Section: N -Centered Radical Generation From N–h Bonds Through Photochemical and Electrochemical Pcet Processesmentioning

confidence: 99%

Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis

et al. 2021

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“…Another visible light irradiated CÀ N bond formation in phenanthridinones has been demonstrated by Usami et al [30] The intramolecular CÀ H amidation of N-aryl biphenyl carboxamide could be achieved in presence of 1-chloroanthraquinone as a photocatalyst and K 2 CO 3 as an additive under transitionmetal-free conditions (Scheme 31). The reaction offered a wide substrate scope where electron-deficient aromatic rings on nitrogen atom and even heterocycles worked as efficient coupling partners, however, alkyl substituted substrates failed to afford the desired product.…”

Section: Reactions Involving Radical Intermediatesmentioning

confidence: 90%

Latest Advancements in Transition‐Metal‐Free Carbon‐Heteroatom Bond Formation Reactions via Cross‐ Dehydrogenative Coupling

Batra¹,

Singh

2021

Asian J Org Chem

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The development of greener and atom economical methods for carbon-heteroatom (CÀ Het) bond formation is of significant importance in synthetic organic chemistry. In this regard, metal-free cross-dehydrogenative coupling (CDC) represents an attractive approach as it is more facile and environment friendly. This review intends to focus on the recent developments in metal-free CDC reactions for CÀ Het bond formation leading to the synthesis

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“…Recently, Itoh et al developed a transition metal free alternative for visible light-mediated cyclization of benzamides 39 into phenathridinones 40 ( Scheme 22 ) [ 142 ]. As a photocatalyst, 1-chloroanthraquinone 41 was employed.…”

Section: Photo-mediated Reactions For Phenanthridinone Synthesismentioning

confidence: 99%

“…Scheme 21. Visible light-induced synthesis of phenanthridinones through direct oxidative C-H amidation.Recently, Itoh et al developed a transition metal free alternative for visible lightmediated cyclization of benzamides 39 into phenathridinones 40 (Scheme 22)[142]. As a photocatalyst, 1-chloroanthraquinone 41 was employed.…”

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confidence: 99%

Synthetic Strategies in the Preparation of Phenanthridinones

et al. 2021

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Phenanthridinones are important heterocyclic frameworks present in a variety of complex natural products, pharmaceuticals and displaying wide range of pharmacological actions. Its structural importance has evoked a great deal of interest in the domains of organic synthesis and medicinal chemistry to develop new synthetic methodologies, as well as novel compounds of pharmaceutical interest. This review focuses on the synthesis of phenanthridinone scaffolds by employing aryl-aryl, N-aryl, and biaryl coupling reactions, decarboxylative amidations, and photocatalyzed reactions.

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Transition‐Metal‐Free Synthesis of Phenanthridinones through Visible‐Light‐Driven Oxidative C–H Amidation

Cited by 20 publications

References 34 publications

Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis

Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis

Latest Advancements in Transition‐Metal‐Free Carbon‐Heteroatom Bond Formation Reactions via Cross‐ Dehydrogenative Coupling

Synthetic Strategies in the Preparation of Phenanthridinones

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