Electrochemical‐Induced Ring Transformation of Cyclic α‐(<i>ortho</i>‐Iodophenyl)‐β‐oxoesters

The critical aspects of the corrosion of metal electrodes in cathodic reductions are covered. We discuss the involved mechanisms including alloying with alkali metals, cathodic etching in aqueous and aprotic media, and formation of metal hydrides and organometallics. Successful approaches that have been implemented to suppress cathodic corrosion are reviewed. We present several examples from electroorganic synthesis where the clever use of alloys instead of soft neat heavy metals and the application of protective cationic additives have allowed to successfully exploit these materials as cathodes. Because of the high overpotential for the hydrogen evolution reaction, such cathodes can contribute toward more sustainable green synthetic processes. The reported strategies expand the applications of organic electrosynthesis because a more negative regime is accessible within protic media and common metal poisons, e.g., sulfur-containing substrates, are compatible with these cathodes. The strongly diminished hydrogen evolution side reaction paves the way for more efficient reductive electroorganic conversions.

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“…In this reaction, the lead cathode gave a slightly lower yield than leaded bronze alloy CuSn17Pb. 256 …”

Section: Examples In Reductive Electroorganic Synthesismentioning

confidence: 99%

“…Strehl, Christoffers et al studied the cathodic reduction of α-( ortho -iodophenyl)-β-oxoester cyclization (Scheme ). In this reaction, the lead cathode gave a slightly lower yield than leaded bronze alloy CuSn17Pb …”

Section: Examples In Reductive Electroorganic Synthesismentioning

confidence: 99%

Cathodic Corrosion of Metal Electrodes—How to Prevent It in Electroorganic Synthesis

et al. 2021

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“…In 2020, Christoffers and co‐workers reported electrochemical mediated two‐carbon ring‐expansion reaction for the synthesis of benzannulated cycloalkanone carboxylic esters (Scheme 53). [67] TMSCl was used as an additive to facilitate the nucleophilic addition by coordinating with the keto group. The scope of the reaction was investigated by varying ring sizes and the substituents on the aryl ring (products 205 – 207 ).…”

Section: Miscellaneous Reagents Mediated Dowd–beckwith Reactionmentioning

confidence: 99%

The Dowd–Beckwith Reaction: History, Strategies, and Synthetic Potential

Singha

Mondal

Midya

et al. 2022

Chemistry A European J

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Ring-expansion strategies are valuable synthetic tools that take benefit of existing ring structures and evade the unfavorable enthalpic-and entropic effects that arise with end-to-end cyclizations. One potentially important class of such reactions is the Dowd-Beckwith reaction, the ringexpansion of ketones via alkoxy radicals. The exciting advancement in this research area is starting to show its potential, as demonstrated by applying this methodology in strategy-level bond formation to synthesize complex natural products. This Review aims to provide the first comprehensive survey of the development of the Dowd-Beckwith reaction spanning three decades from the initial report to the present day, thus providing the readers with great detail about the contributions of this reaction to organic synthesis. We hope that this review will further disclose the salient features of the Dowd-Beckwith reaction for synthetic applications and encourage the development of new, more advanced applications.

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“… Recently, a novel ring-expanding reaction pathway was realized for the generation of benzannulated cycloalkanone carboxylic esters from iodobenzene derivatives in the presence of TMSCl by a formal 1,3-acyl-shift (Scheme ). An electroreduction of the iodobenzene derivatives initiated this reaction sequence which proceeded by nucleophilic addition of the carbanion to the carbonyl group followed by C–C bond cleavage by retro-aldol reaction.…”

Section: Cleavage Of C–c Single Bondsmentioning

confidence: 99%

Electrochemical Oxidation Induced Selective C–C Bond Cleavage

2020

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Selective C−C bond cleavage under mild conditions can serve as a valuable tool for organic syntheses and macromolecular degradation. However, the conventional chemical methods have largely involved the use of noble transition-metal catalysts as well as the stoichiometric and perhaps environmentally unfriendly oxidants, compromising the overall sustainable nature of C−C transformation chemistry. In this regard, electrochemical C−C bond cleavage has been identified as a sustainable and scalable strategy that employs electricity to replace byproduct-generating chemical reagents. To date, the progress made in this area has mainly relied on Kolbe electrolysis and related processes. Encouragingly, more and more examples of the cleavage of C−C bonds via other maneuvers have recently been developed. This review provides an overview on the most recent and significant developments in electrochemically oxidative selective C−C bond cleavage, with an emphasis on both synthetic outcomes and reaction mechanisms, and it showcases the innate advantages and exciting potentials of electrochemical synthesis. CONTENTS 1. Introduction 485 2. Cleavage of C−C Single Bonds 486 2.1. Kolbe Electrolysis and Related Processes 486 2.2. Cleavage of C sp 3 −C(O) Bonds 490 2.3. Cleavage of Vicinal Difunctional Compounds' C−C Bonds 492 2.4. Cleavage of C sp 2 −C Bonds 493 2.5. Cleavage of Bridged and Strained Cyclic C− C Bonds 495 2.6. Cleavage of C−C Bonds via Migration Reactions 497 3. Cleavage of CC Double Bonds 497 3.1. Oxygenation of CC to Carbonyl Compounds 497 3.2. Oxygenation of CC to Carboxyl Compounds 500 4. Conclusion and

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Electrochemical‐Induced Ring Transformation of Cyclic α‐(ortho‐Iodophenyl)‐β‐oxoesters

Cited by 13 publications

References 39 publications

Cathodic Corrosion of Metal Electrodes—How to Prevent It in Electroorganic Synthesis

Cathodic Corrosion of Metal Electrodes—How to Prevent It in Electroorganic Synthesis

The Dowd–Beckwith Reaction: History, Strategies, and Synthetic Potential

Electrochemical Oxidation Induced Selective C–C Bond Cleavage

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