Oxidative (Cross-)Coupling Reactions Mediated by C-H Activation of Thiophene Derivatives by Using Molybdenum(V) Reagents

Oxidative coupling by using molybdenum pentachloride provides fast and modular access to sophisticated thienoacenes in excellent yields. The coupling process can be accomplished with thiophene and benzothiophene derivatives and provides various complex skeletons such as spirocyclic compounds. In this approach, the first cross-coupling reactions with the use of MoCl5 were established and important motifs for semiconducting materials were synthesized.

About the selectivity and reactivity of active nickel electrodes in C–C coupling reactions

Active anodes which are operating in highly stable protic media such as 1,1,1,3,3,3-hexafluoroisopropanol are rare. Nickel forms, within this unique solvent, a non-sacrificial active anode at constant current conditions, which is superior to the reported powerful molybdenum system. The reactivity for dehydrogenative coupling reactions of this novel active anode increases when the electrolyte is not stirred during electrolysis. Besides the aryl-aryl coupling, a dehydrogenative arylation reaction of benzylic nitriles was found while stirring the mixture providing quick access to synthetically useful building blocks.

ChemInform Abstract: Oxidative (Cross-)Coupling Reactions Mediated by C-H Activation of Thiophene Derivatives by Using Molybdenum(V) Reagents.

The use of MoCl5 renders possible the preparation of various synthetically important polycyclic thienoacenes.

Innentitelbild: Reagens- und metallfreie anodische C-C-Kreuzkupplung von Anilinderivaten (Angew. Chem. 17/2017)

Direct Anodic Dehydrogenative Cross- and Homo-Coupling of Formanilides

Inside Cover: Reagent- and Metal-Free Anodic C−C Cross-Coupling of Aniline Derivatives (Angew. Chem. Int. Ed. 17/2017)

Outstandingly robust anodic dehydrogenative aniline coupling reaction

Abstract Oxidative treatment of anilines usually leads to the formation of black polymers, often referred to as “aniline black”. This over-oxidation is hardly controllable and also a challenging task in the anodic conversion of anilines. Here, a quick and efficient access to valuable building blocks by anodic cross- and homo-coupling of aniline and benzidine derivatives is reported. This electrosynthesis is easily performed in a simple undivided cell using constant current conditions. The key to the observed outstanding performance and robustness of this system is attributed to the used solvent 1,1,1,3,3,3-hexafluoroisopropanol. The extraordinary performance over a broad range of current de…

Reagens- und metallfreie anodische C-C-Kreuzkupplung von Anilinderivaten

Vorgestellt wird die oxidative Kreuzkupplung von Anilinderivaten zu 2,2′-Diaminobiarylen. Der Oxidationsschritt wird elektrochemisch durchgefuhrt, ohne die Notwendigkeit von Metallen und Reagenzien. Ein breites Spektrum an Biphenyldiaminen konnte hergestellt werden. Die besten Resultate wurden mit Glaskohlenstoff als Anodenmaterial erhalten. Die elektrochemische Umsetzung kann problemlos in einer ungeteilten Zelle bei leicht erhohten Temperaturen durchgefuhrt werden. Auserdem wurden gebrauchliche, auf Carbonsauren basierende, Schutzgruppen verwendet, die nach der Kreuzkupplung unter milden Bedingungen selektiv abgespalten werden konnen. Auf diese Weise erhalt man schnell und effizient Zugan…

Solvent Control in Electro-Organic Synthesis

Exploiting the solvent control within electro-organic conversions is a far underestimated parameter in prep-scale electrolysis. The beneficial application in several transformations is outlined and in particular discussed for the dehydrogenative coupling of arenes and heteroarenes. This simple electrolytic strategy in fluorinated solvents allows the modulation of the substrate’s nucleophilicity and the stabilization of the intermediates as well as of the final product from over-oxidation.1 Introduction2 Solvent Effects in Kolbe Electrolysis and Anodic Fluorination3 Unique Solvent Effects of 1,1,1,3,3,3-Hexafluoropropan-2-ol (HFIP)4 Anodic Dehydrogenative Coupling Reactions with Use of HFIP …

Reagent- and Metal-Free Anodic C-C Cross-Coupling of Aniline Derivatives.

The dehydrogenative cross-coupling of aniline derivatives to 2,2′-diaminobiaryls is reported. The oxidation is carried out electrochemically, which avoids the use of metals and reagents. A large variety of biphenyldiamines were thus prepared. The best results were obtained when glassy carbon was used as the anode material. The electrosynthetic reaction is easily performed in an undivided cell at slightly elevated temperature. In addition, common amine protecting groups based on carboxylic acids were employed that can be selectively removed under mild conditions after the cross-coupling, which provides quick and efficient access to important building blocks featuring free amine moieties.

CCDC 1517624: Experimental Crystal Structure Determination

Related Article: Lara Schulz, Mathias Enders, Bernd Elsler, Dieter Schollmeyer, Katrin M. Dyballa, Robert Franke, Siegfried R. Waldvogel|2017|Angew.Chem.,Int.Ed.|56|4877|doi:10.1002/anie.201612613

CCDC 1517625: Experimental Crystal Structure Determination

Related Article: Lara Schulz, Mathias Enders, Bernd Elsler, Dieter Schollmeyer, Katrin M. Dyballa, Robert Franke, Siegfried R. Waldvogel|2017|Angew.Chem.,Int.Ed.|56|4877|doi:10.1002/anie.201612613

CCDC 1976461: Experimental Crystal Structure Determination

Related Article: Sebastian B. Beil, Manuel Breiner, Lara Schulz, Aaron Schüll, Timo Müller, Dieter Schollmeyer, Alexander Bomm, Michael Holtkamp, Uwe Karst, Wolfgang Schade, Siegfried R. Waldvogel|2020|RSC Advances|10|14249|doi:10.1039/D0RA02673E