Electrohalogenation of propargyl acetates and amides to form the 1,1-dibromo-2-oxo functionality and a facile synthesis of furaneol

Inokuchi, Tsutomu; Matsumoto, Sigeaki; Tsuji, Michihiro; Torii, Sigeru

doi:10.1021/jo00044a047

Cited by 34 publications

(11 citation statements)

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“…This journal is © The Royal Society of Chemistry 2014 two-phase mixture of CH 2 Cl 2 and aqueous 25% NaBr solution buffered with NaCO 3 /NaHCO 3 (see Scheme 20). 52 The oxidation was carried out in an undivided cell under galvanostatic conditions using platinum electrodes, and with an isolated yield of 88%. The scope was extended to other propargyl acetates leading to similarly high yields.…”

Section: Anodic Oxidationmentioning

confidence: 99%

Redox catalysis in organic electrosynthesis: basic principles and recent developments

2014

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Electroorganic synthesis has become an established, useful, and environmentally benign alternative to classic organic synthesis for the oxidation or the reduction of organic compounds. In this context, the use of redox mediators to achieve indirect processes is attaining increased significance, since it offers many advantages compared to a direct electrolysis. Kinetic inhibitions that are associated with the electron transfer at the electrode/electrolyte interface, for example, can be eliminated and higher or totally different selectivity can be achieved. In many cases, a mediated electron transfer can occur against a potential gradient, meaning that lower potentials are needed, reducing the probability of undesired side-reactions. In addition, the use of electron transfer mediators can help to avoid electrode passivation resulting from polymer film formation on the electrode surface. Although the principle of indirect electrolysis was established many years ago, new, exciting and useful developments continue to be made. In recent years, several new types of redox mediators have been designed and examined, a process that can be accomplished more efficiently and purposefully using modern computational tools. New protocols including, the development of double mediatory systems in biphasic media, enantioselective mediation and heterogeneous electrocatalysis using immobilized mediators have been established. Furthermore, the understanding of mediated electron transfer reaction mechanisms has advanced. This review describes progress in the field of electroorganic synthesis and summarizes recent advances.

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Section: Anodic Oxidationmentioning

confidence: 99%

Redox catalysis in organic electrosynthesis: basic principles and recent developments

2014

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“…In 1992, Torii and co-workers expanded upon their work with biphasic aminoxyl/bromide co-mediated electrolysis by exploring the synthesis of α,α-dihaloketones from alkynes (Scheme ). These products represent an appealing synthetic alternative to relatively unstable 1,2-diketones. , The reaction was proposed to proceed via oxidation of Br – to Br + or Br • , either of which could react with the alkyne. Pendant acetate and amide groups and water are thought to subsequently participate in oxygenation of the activated alkyne (e.g., as a bromonium species).…”

Section: Electrochemical Reactions Mediated By Tempo and Related Cycl...mentioning

confidence: 99%

Tetramethylpiperidine N-Oxyl (TEMPO), Phthalimide N-Oxyl (PINO), and Related N-Oxyl Species: Electrochemical Properties and Their Use in Electrocatalytic Reactions

2018

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N-Oxyl compounds represent a diverse group of reagents that find widespread use as catalysts for the selective oxidation of organic molecules in both laboratory and industrial applications. While turnover of N-oxyl catalysts in oxidation reactions may be accomplished with a variety of stoichiometric oxidants, N-oxyl reagents have also been extensively used as catalysts under electrochemical conditions in the absence of chemical oxidants. Several classes of N-oxyl compounds undergo facile redox reactions at electrode surfaces, enabling them to mediate a wide range of electrosynthetic reactions. Electrochemical studies also provide insights into the structural properties and mechanisms of chemical and electrochemical catalysis by N-oxyl compounds. This review provides a comprehensive survey of the electrochemical properties and electrocatalytic applications of aminoxyls, imidoxyls, and related reagents, of which the two prototypical and widely used examples are 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) and phthalimide N-oxyl (PINO).

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“…Currently, electrocatalysts in organic syntheses are primarily limited to pure electron mediators and hydrogen atom abstraction catalysts . As classical examples, halogen anions, triarylamines, benzoquinones, nitroxyl radicals, phenanthroimizazoles, and ferrocenes have been demonstrated as highly efficient mediators for reactions such as alkene functionalization and alcohol oxidation, and these protocols have been used in efficient syntheses of complex target molecules (Scheme B).…”

Section: Introductionmentioning

confidence: 99%

An Electrocatalytic Approach to the Radical Difunctionalization of Alkenes

2018

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Given its many distinct characteristics, electrochemistry represents an attractive approach to meet the prevailing trends in organic synthesis. In particular, electrocatalysisa process that integrates electrochemistry and small-molecule catalysishas the potential to substantially improve the scope of synthetic electrochemistry and provide a wide range of useful transformations. Recently, we have demonstrated new catalytic approaches that combine electrochemistry and redox-metal catalysis for the oxidative difunctionalization of alkenes to access a diverse array of vicinally functionalized structures. This Perspective details our design principles underpinning the development of electrochemical diazidation, dichlorination, and halotrifluoromethylation of alkenes, which were built on foundational work by others in the areas of synthetic electrochemistry, radical chemistry, and transition-metal catalysis. The introduction of redox-active Mn catalysts allows the generation of radical intermediates from readily available reagents at low potentials under mild conditions. These transition metals also impart selectivity control over the alkene functionalization processes by functioning as radical group transfer agents. As such, our electrocatalytic difunctionalization reactions exhibit excellent chemoselectivity, broad substrate scope, and high functional group compatibility. Specifically, anodically coupled electrolysis, an approach that pairs two single-electron oxidation events in a parallel manner, enables the development of regio- and chemoselective heterodifunctionalization of alkenes. The products of the new transformations we describe in this Perspective represent pertinent structures in numerous medicinally relevant compounds. We anticipate that the design parameters presented here are general and will provide a platform for the development of electrocatalytic systems for other challenging organic redox transformations.

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Electrohalogenation of propargyl acetates and amides to form the 1,1-dibromo-2-oxo functionality and a facile synthesis of furaneol

Cited by 34 publications

References 0 publications

Redox catalysis in organic electrosynthesis: basic principles and recent developments

Redox catalysis in organic electrosynthesis: basic principles and recent developments

Tetramethylpiperidine N-Oxyl (TEMPO), Phthalimide N-Oxyl (PINO), and Related N-Oxyl Species: Electrochemical Properties and Their Use in Electrocatalytic Reactions

An Electrocatalytic Approach to the Radical Difunctionalization of Alkenes

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