Manganese-Catalyzed Oxidative Azidation of C(sp3)-H Bonds under Electrophotocatalytic Conditions.
17 Sep 2020-Journal of the American Chemical Society (American Chemical Society)-Vol. 142, Iss: 41, pp 17693-17702
TL;DR: This work demon-strate a generalized manganese-catalyzed oxidative azidation meth-odology of C(sp3)-H bonds using nucleophilic NaN3 as an azide source under electrophotocatalytic conditions and expects this synthetic protocol, consisting of metal catalysis, electrochemistry and photochemistry, would pro-vide a new sustainable option to execute challenging organic syn-thetic transformations.
Abstract: The selective installation of azide groups into C(sp3)–H bonds is a priority research topic in organic synthesis, particularly in pharmaceutical discovery and late-stage diversification. Herein, we...
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TL;DR: In this article, a review highlights key innovations within the past decade in the area of synthetic electrocatalysis, with emphasis on the mechanisms and catalyst design principles underpinning these advancements, and a host of oxidative and reductive electrocatalytic methodologies are discussed and grouped according to the classification of the synthetic transformation and the nature of the electrocatalyst.
Abstract: Electrochemistry has recently gained increased attention as a versatile strategy for achieving challenging transformations at the forefront of synthetic organic chemistry. Electrochemistry's unique ability to generate highly reactive radical and radical ion intermediates in a controlled fashion under mild conditions has inspired the development of a number of new electrochemical methodologies for the preparation of valuable chemical motifs. Particularly, recent developments in electrosynthesis have featured an increased use of redox-active electrocatalysts to further enhance control over the selective formation and downstream reactivity of these reactive intermediates. Furthermore, electrocatalytic mediators enable synthetic transformations to proceed in a manner that is mechanistically distinct from purely chemical methods, allowing for the subversion of kinetic and thermodynamic obstacles encountered in conventional organic synthesis. This review highlights key innovations within the past decade in the area of synthetic electrocatalysis, with emphasis on the mechanisms and catalyst design principles underpinning these advancements. A host of oxidative and reductive electrocatalytic methodologies are discussed and are grouped according to the classification of the synthetic transformation and the nature of the electrocatalyst.
316 citations
TL;DR: A comprehensive review of the synthetic applications of photocatalyzed d-HAT can be found in this article, where the authors provide a comprehensive overview of the main applications of PCHAT.
Abstract: Direct photocatalyzed hydrogen atom transfer (d-HAT) can be considered a method of choice for the elaboration of aliphatic C-H bonds. In this manifold, a photocatalyst (PCHAT) exploits the energy of a photon to trigger the homolytic cleavage of such bonds in organic compounds. Selective C-H bond elaboration may be achieved by a judicious choice of the hydrogen abstractor (key parameters are the electronic character and the molecular structure), as well as reaction additives. Different are the classes of PCsHAT available, including aromatic ketones, xanthene dyes (Eosin Y), polyoxometalates, uranyl salts, a metal-oxo porphyrin and a tris(amino)cyclopropenium radical dication. The processes (mainly C-C bond formation) are in most cases carried out under mild conditions with the help of visible light. The aim of this review is to offer a comprehensive survey of the synthetic applications of photocatalyzed d-HAT.
261 citations
19 Aug 2021
TL;DR: Recently, photo-induced intermolecular HAT reactions have seen substantial development of their versatility, efficiency, and selectivity, and a recent review summarizes recent advances in this rapidly expanding research area as mentioned in this paper.
Abstract: Summary Hydrogen-atom transfer (HAT) provides straightforward methods to generate open-shell radical intermediates from R-H (R = C, Si, etc.) bonds and offers unique opportunities for green and sustainable synthesis. Traditional HAT protocols required harsh conditions and relied on the use of harmful reagents such as Cl2 and peroxides. An emerging strategy is photoinduced intermolecular HAT, in which transformations can be driven by photocatalysis under mild conditions. In recent years, photoinduced intermolecular HAT reactions have seen substantial development of their versatility, efficiency, and selectivity. This review summarizes recent advances (up to December 2020) in this rapidly expanding research area. The representative examples provided are classified according to the active species responsible for hydrogen atom abstraction. The reactivity, selectivity, and established transformations for each type of active species are briefly summarized. This review aims to provide guidance for the application of photoinduced HAT in R-H functionalization reactions and to inspire further progress in this research area.
133 citations
Cites methods from "Manganese-Catalyzed Oxidative Azida..."
...Miscellaneous examples In 2020, Lei and co-workers demonstrated a manganese-catalyzed C(sp(3))-H azidation under electrophotocatalytic conditions with nucleophilic sodium azide as the azidation reagent (Scheme 32).(65) The use of excess substrate or stoichiometric chemical oxidant was avoided by merging the C(sp(3))-H abstracting ability of ketone photocatalysts with sustainable electrochemical oxidation and manganese-assisted radical azidation....
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TL;DR: In this article, a review of the recent research progress in the area of indirect electrolysis using transition metals is presented, which is the impetus for this review. But there is a lack of articles that focus on the recent progress in indirect organic electrosynthesis using transition metal.
Abstract: Organic electrosynthesis has been widely used as an environmentally conscious alternative to conventional methods for redox reactions because it utilizes electric current as a traceless redox agent instead of chemical redox agents. Indirect electrolysis employing a redox catalyst has received tremendous attention, since it provides various advantages compared to direct electrolysis. With indirect electrolysis, overpotential of electron transfer can be avoided, which is inherently milder, thus wide functional group tolerance can be achieved. Additionally, chemoselectivity, regioselectivity, and stereoselectivity can be tuned by the redox catalysts used in indirect electrolysis. Furthermore, electrode passivation can be avoided by preventing the formation of polymer films on the electrode surface. Common redox catalysts include N-oxyl radicals, hypervalent iodine species, halides, amines, benzoquinones (such as DDQ and tetrachlorobenzoquinone), and transition metals. In recent years, great progress has been made in the field of indirect organic electrosynthesis using transition metals as redox catalysts for reaction classes including C–H functionalization, radical cyclization, and cross-coupling of aryl halides-each owing to the diverse reactivity and accessible oxidation states of transition metals. Although various reviews of organic electrosynthesis are available, there is a lack of articles that focus on recent research progress in the area of indirect electrolysis using transition metals, which is the impetus for this review.
115 citations
01 May 2021
TL;DR: In this article, a review of recent advances in the chemistry of electrochemically generated nitrogen-centered radicals (NCRs) is presented, based on the electrochemical strategies for their formation and the types of NCRs.
Abstract: There is a resurgence of interests in organic electrochemistry, which is generally accepted as a green synthetic tool. In this context, many electrochemical methods have been developed in the past decade to access various nitrogen-centered radicals (NCRs) from readily available precursors in a controlled fashion, enabling the rapid development of many NCR-mediated new reactions for the construction of nitrogen-containing organic compounds. In this review, recent advances in the chemistry of electrochemically generated NCRs are critically highlighted, based on the electrochemical strategies for their formation and the types of NCRs. Focus is put on the mechanism for the electrochemical generation of different NCRs and their synthetic applications.
100 citations
References
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TL;DR: In this Review, the fundamental characteristics of azide chemistry and current developments are presented and the focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles.
Abstract: Since the discovery of organic azides by Peter Griess more than 140 years ago, numerous syntheses of these energy-rich molecules have been developed. In more recent times in particular, completely new perspectives have been developed for their use in peptide chemistry, combinatorial chemistry, and heterocyclic synthesis. Organic azides have assumed an important position at the interface between chemistry, biology, medicine, and materials science. In this Review, the fundamental characteristics of azide chemistry and current developments are presented. The focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles. Further reactions such as the aza-Wittig reaction, the Sundberg rearrangement, the Staudinger ligation, the Boyer and Boyer-Aube rearrangements, the Curtius rearrangement, the Schmidt rearrangement, and the Hemetsberger rearrangement bear witness to the versatility of modern azide chemistry.
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TL;DR: This Review comprehensively highlights recent advances in intra- and intermolecular C-H amination reactions utilizing late transition metal-based catalysts using mechanistic scaffolds and types of reactions.
Abstract: Catalytic transformation of ubiquitous C–H bonds into valuable C–N bonds offers an efficient synthetic approach to construct N-functionalized molecules. Over the last few decades, transition metal catalysis has been repeatedly proven to be a powerful tool for the direct conversion of cheap hydrocarbons to synthetically versatile amino-containing compounds. This Review comprehensively highlights recent advances in intra- and intermolecular C–H amination reactions utilizing late transition metal-based catalysts. Initial discovery, mechanistic study, and additional applications were categorized on the basis of the mechanistic scaffolds and types of reactions. Reactivity and selectivity of novel systems are discussed in three sections, with each being defined by a proposed working mode.
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TL;DR: The present review will focus mainly on the recent literature for applications of this reaction in the field of medicinal chemistry, in particular on use of the 1,2,3-triazole moiety as pharmacophore.
Abstract: The copper(I)-catalyzed 1,2,3-triazole-forming reaction between azides and terminal alkynes has become the gold standard of 'click chemistry' due to its reliability, specificity, and biocompatibility. Applications of click chemistry are increasingly found in all aspects of drug discovery; they range from lead finding through combinatorial chemistry and target-templated in vitro chemistry, to proteomics and DNA research by using bioconjugation reactions. The triazole products are more than just passive linkers; they readily associate with biological targets, through hydrogen-bonding and dipole interactions. The present review will focus mainly on the recent literature for applications of this reaction in the field of medicinal chemistry, in particular on use of the 1,2,3-triazole moiety as pharmacophore.
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