Electrochemical hydrogenation of α-ketoesters and benzoxazinones using carbon electrodes and a sustainable Brønsted acid

Nemez, Dion B.; Sidhu, Baldeep K.; Giesbrecht, Patrick K.; Braun, Jason D.; Herbert, David E.

doi:10.1039/d0qo01311k

Cited by 8 publications

(9 citation statements)

References 41 publications

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“…28,29 This latter reactivity can be realized electrochemically, 30 with implications for N-heterocycle-mediated electrochemical CO 2 reduction 31 and methodologies for electrochemical hydrogenation. 32 The ease with which phenanthridine's C=N bond can be selectively reduced can be understood by considering that phenanthridine has three (fused) six-membered rings but only 14 electrons. The 'imine-bridged biphenyl' resonance structure contributes most strongly to the ground state structure as it maximizes the number of aromatic sextets which can be drawn (Figure 3a).…”

Section: Stabilization Of Reactive Intermediates In Catalysismentioning

confidence: 99%

When is a pyridine not a pyridine? Benzannulated N-heterocyclic ligands in molecular materials chemistry

Herbert

2023

Can. J. Chem.

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The C=N bond is a critical structural piece of many N-donor ligand scaffolds and is central to the properties and reactivity of important coordination complexes. For example, C=N units play a key role in the ‘redox non-innocence’ of α-diimine complexes and in making charge-transfer excited-state character available to complexes of N-heterocyclic ligands such as bipyridine. In N-heterocycles like pyridine, benzannulation can be used to extend the conjugated C=N containing π-system to quinoline (2,3-benzopyridine) to acridine (2,3-benzoquinoline). This stabilizes the lowest unoccupied molecular orbital (LUMO) of the molecule and boosts its electron-accepting properties, but the position of the benzannulation matters. For example, phenanthridine (3,4-benzoquinoline), an asymmetric isomer of acridine, bears a similarly electronically accessible extended π-system but more chemically isolated, ‘imine-like’ C=N moiety. This Award Paper presents an overview of our work investigating the impact of such site-selective benzannulation on the chemistry and properties of phenanthridine as a molecule and ligand.

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Section: Stabilization Of Reactive Intermediates In Catalysismentioning

confidence: 99%

When is a pyridine not a pyridine? Benzannulated N-heterocyclic ligands in molecular materials chemistry

Herbert

2023

Can. J. Chem.

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“…α-ketoesters also undergo reduction in the above mentioned conditions. [42] During the same year, Waldvogel's group accessed the formamidine acetate having synthetic versatility by exploring the electroreduction of cyanamide in acidic aqueous media in which scale-up synthesis was achieved using electrolyte-free continuous flow strategy by employing a narrow gap cell to achieve high yields. [43] In 2020, the groups of Yen, Yang, and Wang reported a new dearomative transfer hydrogenation of heteroaromatic systems containing N-atoms, viz.…”

Section: Reductive Hydrogenation Of Cà N Bondmentioning

confidence: 99%

“…In 2021, Herbert and co‐workers, in acidic media, realized electrochemical hydrogenation of C=N bonds in benzoxazinones in presence of a RVC working electrode. α ‐ketoesters also undergo reduction in the above mentioned conditions [42] . During the same year, Waldvogel's group accessed the formamidine acetate having synthetic versatility by exploring the electroreduction of cyanamide in acidic aqueous media in which scale‐up synthesis was achieved using electrolyte‐free continuous flow strategy by employing a narrow gap cell to achieve high yields [43] …”

Section: Reduction Of C−n Bondmentioning

confidence: 99%

Cathodic Electrolysis: Electroreductive Organic Synthesis

Lingden,

Pokhrel

et al. 2023

ChemElectroChem

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Cathodic reductive electrolysis in organic transformations is used to generate radical anions. These electrochemical reduction reactions are very useful in various carbonyl groups transformation (such as aldehydes, ketones, esters, and amides), new bond formations as well as reduction of saturated and unsaturated molecules. Reductive electrocarboxylation reactions to access various valuable chemicals are one of the important applications of cathodic reductive electrolysis. Herein, we review particularly the electrochemical organic transformation reactions taking place at the cathode. We also discuss how alternative strategies such as paired electrolysis, photo‐electrolysis, and alternating current electrolysis can be used to overcome the limitations associated with cathodic electrolysis and how they will improve sustainable electrochemical transformations.

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“…Recently, they also reported a methodology for selective hydrogenation of aryl‐substituted α‐ketoesters and benzoxazinones by using carbon as the electrodes and CH 3 COOH as hydrogen donors (Scheme 19). [28] …”

Section: Electrochemical Hydrogenationmentioning

confidence: 99%

Advances in Electrochemical Hydrogenation Since 2010

et al. 2021

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A commitment to developing a convenient, efficient, and safe hydrogenation strategy is one of the main focuses of industry and academia. Electrochemical hydrogenation brings greener and gentler opportunities for the selective hydrogenation of unsaturated compounds and the incorporation of deuterium atoms to desired products with traceless electrons as redox reagents in the absence of highpressure hydrogen. In this account, recent advances in electrochemical hydrogenation or transfer hydrogenation of unsaturated compounds since 2010 are summarized. The reaction features, limitations, substrates scopes, mechanism of these hydrogenation reactions are discussed in this review. We hope this account will contribute to future developments to broaden the scope of electrochemical hydrogenation or transfer hydrogenation. Alkenes and Alkynes 2.3. Electrochemical Hydrogenation of Unactivated Alkenes and Alkynes 2.4. Electrochemical Hydrogenation of N-Heteroaromatics 2.5. Electrochemical Birch Reduction 3. Conclusion

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Electrochemical hydrogenation of α-ketoesters and benzoxazinones using carbon electrodes and a sustainable Brønsted acid

Abstract: The direct electrochemical hydrogenation of unsaturated organic compounds containing C=N and C=O bonds using glassy carbon electrodes and widely available Brønsted acids is demonstrated for a selection of α-ketoesters and...

Cited by 8 publications

References 41 publications

When is a pyridine not a pyridine? Benzannulated N-heterocyclic ligands in molecular materials chemistry

When is a pyridine not a pyridine? Benzannulated N-heterocyclic ligands in molecular materials chemistry

Cathodic Electrolysis: Electroreductive Organic Synthesis

Advances in Electrochemical Hydrogenation Since 2010

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