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.

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 as the Solvent5 Conclusion

The direct anodic dehydrogenative C−C cross‐ and homo‐coupling of formanilides is reported. This exceptional electrochemical synthesis allows one to prepare a broad variety of non‐symmetrical and symmetrical 2,2′‐diformamidobiphenyls as well as 2‐formamido‐2′‐amidobiphenyls. By applying an easy and simple to perform metal‐ and oxidizer‐free electrochemical protocol, and the formyl group as a highly atom‐economic amino‐protecting group, an important contribution to a sustainable and green‐minded chemistry was achieved.

Vorgestellt wird die oxidative Kreuzkupplung von Anilinderivaten zu 2,2'-Diaminobiarylen. Der Oxidationsschritt wird elektrochemisch durchgeführt, 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 leichte rhçhten Temperaturen durchgeführt werden. Außerdem wurden gebräuchliche,a uf Carbonsäuren basierende,Schutzgruppen verwendet, die nach der Kreuzkupplung unter milden Bedingungen selektiv abgespalten werden kçnnen. Aufd iese Weise erhält man schnell und effizient Zugang zu äußerst wichtigen Bausteinen.

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.