Metal- and Reagent-Free Anodic C−C Cross-Coupling of Phenols with Benzofurans leading to a Furan Metathesis

Heterobiaryls consisting of a phenol and a benzofuran motif are of significant importance for pharmaceutical applications. An attractive sustainable, metal- and reagent-free, electrosynthetic, and highly efficient method, that allows access to (2-hydroxyphenyl)benzofurans is presented. Upon the electrochemical dehydrogenative C-C cross-coupling reaction, a metathesis of the benzo moiety at the benzofuran occurs. This gives rise to a substitution pattern at the hydroxyphenyl moiety which would not be compatible by a direct coupling process. The single-step protocol is easy to conduct in an undivided electrolysis cell, therefore scalable, and inherently safe.

Einfache und doppelte metall- und reagensfreie anodische C-C-Kreuzkupplung von Phenolen mit Thiophenen

Erstmals ist es gelungen, eine elektrochemische dehydrierende C-C-Kreuzkupplung von Thiophenen mit Phenolen durchzufuhren. Diese nachhaltige und einfache anodische Kreuzkupplung eroffnet den Zugang zu zwei besonders interessanten Substanzklassen. Das Anwendungsgebiet der C-H-aktivierenden elektrochemischen Kreuzkupplung wurde dabei um Schwefelheterocyclen erweitert. Bisher konnten nur verschiedene benzoide aromatische Systeme umgesetzt werden, wohingegen die Verwendung von Heterocyclen bei der C-H-aktivierenden elektrochemischen Kreuzkupplung nicht erfolgreich war. In diesem Fall bieten reagens- und metallfreie Bedingungen einen nachhaltigen elektrochemischen Weg und damit einen vielverspre…

Regioselektive metall‐ und reagenzfreie Arylierung von Benzothiophenen durch dehydrierende Elektrosynthese

Direct Metal‐ and Reagent‐Free Sulfonylation of Phenols with Sodium Sulfinates by Electrosynthesis

A novel electrochemical strategy for the synthesis of aryl sulfones by direct sulfonylation of phenols with sodium sulfinates has been developed. The C,S-coupling products are of particular interest for chemical synthesis, material sciences and pharmaceutical sciences. By using this metal- and reagent-free electrochemical method, aryl and diaryl sulfones can be obtained directly in good yields. The established one-step protocol is easy to perform, scalable, inherently safe, and enables a broad scope, which is not limited by quinoid-forming substrates.

Innentitelbild: Regioselektive metall‐ und reagenzfreie Arylierung von Benzothiophenen durch dehydrierende Elektrosynthese (Angew. Chem. 40/2018)

Inside Cover: Regioselective Metal‐ and Reagent‐Free Arylation of Benzothiophenes by Dehydrogenative Electrosynthesis (Angew. Chem. Int. Ed. 40/2018)

ChemInform Abstract: Synthesis of meta-Terphenyl-2,2′′-diols by Anodic C-C Cross-Coupling Reactions.

The anodic C−C cross-coupling reaction is a versatile synthetic approach to symmetric and non-symmetric biphenols and arylated phenols. We herein present a metal-free electrosynthetic method that provides access to symmetric and non-symmetric meta-terphenyl-2,2′′-diols in good yields and high selectivity. Symmetric derivatives can be obtained by direct electrolysis in an undivided cell. The synthesis of non-symmetric meta-terphenyl-2,2′′-diols required two electrochemical steps. The reactions are easy to conduct and scalable. The method also features a broad substrate scope, and a large variety of functional groups are tolerated. The target molecules may serve as [OCO]3− pincer ligands.

Synthesis ofmeta-Terphenyl-2,2′′-diols by Anodic C−C Cross-Coupling Reactions

The anodic C-C cross-coupling reaction is a versatile synthetic approach to symmetric and non-symmetric biphenols and arylated phenols. We herein present a metal-free electrosynthetic method that provides access to symmetric and non-symmetric meta-terphenyl-2,2''-diols in good yields and high selectivity. Symmetric derivatives can be obtained by direct electrolysis in an undivided cell. The synthesis of non-symmetric meta-terphenyl-2,2''-diols required two electrochemical steps. The reactions are easy to conduct and scalable. The method also features a broad substrate scope, and a large variety of functional groups are tolerated. The target molecules may serve as [OCO](3-) pincer ligands.

Synthese vonmeta-Terphenyl-2,2′′-diolen durch anodische C-C-Kreuzkupplungen

Die anodische C-C-Kreuzkupplung ist eine vielseitig einsetzbare Transformation, die eine gezielte Synthese von Biphenolen und arylierten Phenolen ermoglicht. Wir berichten uber einen ebenfalls elektrosynthetischen, metallfreien Ansatz, der einen Zugang zu symmetrischen und nichtsymmetrischen meta-Terphenyl-2,2′′-diolen in guten Ausbeuten und hoher Selektivitat ermoglicht. Symmetrische Derivate konnen durch eine direkte Synthese in einer ungeteilten Zelle gewonnen werden, wohingegen nichtsymmetrische meta-Terphenyl-2,2′′-diole zwei elektrochemische Stufen benotigen. Die milde Methode ist einfach durchzufuhren und skalierbar. Auserdem konnte erstmalig eine breite Substratvariabilitat aufgezei…

Electrochemical Synthesis of 2-Hydroxy-para-terphenyls by Dehydrogenative Anodic C–C Cross-Coupling Reaction

The anodic C–C cross-coupling reaction provides fast access to a wide range of bi- and terarylic scaffolds by electrochemically mediated arylation reactions. Herein, a metal- and reagent-free electrosynthetic protocol for the synthesis of nonsymmetrical 2-hydroxy-para-teraryl derivatives is presented for the first time. It is scalable, easy to conduct, and allows the use of a broad variety of different functional groups.

Cover Feature: Direct Metal‐ and Reagent‐Free Sulfonylation of Phenols with Sodium Sulfinates by Electrosynthesis (Chem. Eur. J. 28/2019)

Unexpected high robustness of electrochemical cross-coupling for a broad range of current density

Solvent effect enables electrosynthesis of organic compounds with strong variation of electric current at constant efficacy.

Single and Twofold Metal- and Reagent-Free Anodic C-C Cross-Coupling of Phenols with Thiophenes.

The first electrochemical dehydrogenative C-C cross-coupling of thiophenes with phenols has been realized. This sustainable and very simple to perform anodic coupling reaction enables access to two classes of compounds of significant interest. The scope for electrochemical C-H-activating cross-coupling reactions was expanded to sulfur heterocycles. Previously, only various benzoid aromatic systems could be converted, while the application of heterocycles was not successful in the electrochemical C-H-activating cross-coupling reaction. Here, reagent- and metal-free reaction conditions offer a sustainable electrochemical pathway that provides an attractive synthetic method to a broad variety …

Regioselective Metal- and Reagent-Free Arylation of Benzothiophenes by Dehydrogenative Electrosynthesis.

A novel strategy for the synthesis of biaryls consisting of a benzothiophene and a phenol moiety is reported. These heterobiaryls are of utmost interest for pharmaceutical, biological, and high-performance optoelectronic applications. The metal- and reagent-free, electrosynthetic, and highly efficient method enables the generation of 2- and 3-(hydroxyphenyl)benzo[b]thiophenes in a regioselective fashion. The described one-step synthesis is easy to conduct, scalable, and inherently safe. The products are afforded in high yields of up to 88 % and with exquisite selectivity. The reaction also features a broad scope and tolerates a large variety of functional groups.

Synthesis of Highly Functionalized N , N ‐Diarylamides by an Anodic C, N ‐Coupling Reaction

We report an innovative, sustainable and straightforward protocol for the synthesis of N,N-diarylamides equipped with nonprotected hydroxyl groups by using electrosynthesis. The concept allows the application of various substrates furnishing diarylamides with yields up to 57 % within a single and direct electrolytic protocol. The method is thereby easy to conduct in an undivided cell with constant current conditions offering a versatile and short-cut alternative to conventional pathways.

Electrochemical Arylation Reaction

Arylated products are found in various fields of chemistry and represent essential entities for many applications. Therefore, the formation of this structural feature represents a central issue of contemporary organic synthesis. By the action of electricity the necessity of leaving groups, metal catalysts, stoichiometric oxidizers, or reducing agents can be omitted in part or even completely. The replacement of conventional reagents by sustainable electricity not only will be environmentally benign but also allows significant short cuts in electrochemical synthesis. In addition, this methodology can be considered as inherently safe. The current survey is organized in cathodic and anodic con…

Use of Boron‐Doped Diamond Electrodes in Electro‐Organic Synthesis

Electrochemical Oxidative C – C Bond Formation

CCDC 1485994: Experimental Crystal Structure Determination

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CCDC 1569308: Experimental Crystal Structure Determination

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CCDC 1891216: Experimental Crystal Structure Determination

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CCDC 1485996: Experimental Crystal Structure Determination

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CCDC 1589070: Experimental Crystal Structure Determination

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CCDC 1485995: Experimental Crystal Structure Determination

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CCDC 1846985: Experimental Crystal Structure Determination

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CCDC 1846986: Experimental Crystal Structure Determination

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CCDC 1896228: Experimental Crystal Structure Determination

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CCDC 1891217: Experimental Crystal Structure Determination

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CCDC 1589072: Experimental Crystal Structure Determination

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CCDC 1569307: Experimental Crystal Structure Determination

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CCDC 1589071: Experimental Crystal Structure Determination

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CCDC 1485997: Experimental Crystal Structure Determination

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