Modern Electrochemical Aspects for the Synthesis of Value‐Added Organic Products

The use of electricity instead of stoichiometric amounts of oxidizers or reducing agents in synthesis is very appealing for economic and ecological reasons, and represents a major driving force for research efforts in this area. To use electron transfer at the electrode for a successful transformation in organic synthesis, the intermediate radical (cation/anion) has to be stabilized. Its combination with other approaches in organic chemistry or concepts of contemporary synthesis allows the establishment of powerful synthetic methods. The aim in the 21st Century will be to use as little fossil carbon as possible and, for this reason, the use of renewable sources is becoming increasingly impo…

Elektrifizierung der organischen Synthese

Moderne Aspekte der Elektrochemie zur Synthese hochwertiger organischer Produkte

Twofold Electrochemical Amination of Naphthalene and Related Arenes

The twofold, electrochemical amination reaction of polycyclic arenes, e.g. naphthalene (4), via Zincke intermediates is demonstrated for the first time. The installation of the nitrogen functionalities occurs regioselectively in positions 1 and 5 of naphthalene (4). The key for this electro-conversion is boron-doped diamond as anode material. The method of the multi-amination reaction is expanded to other aromatic substrates. A detailed study is provided, covering electrolysis parameters, e.g. anode material, electrolyte system, current density, separator, etc. Despite the moderate yields, this approach offers the first direct electro-synthetic access to diaminated products.

Electrochemical Amination of Less-Activated Alkylated Arenes Using Boron-Doped Diamond Anodes

The anodic C–H amination of aromatic compounds is a powerful and versatile method for the synthesis of aniline derivatives. By using boron-doped diamond (BDD) anodes, a method initially described by Yoshida et al. for electron-rich arenes was expanded to less-activated aromatic systems e.g., simple alkylated benzene derivatives. Anodes based on sp3 carbon seem to be the key for the electrochemical amination reaction. The corresponding primary anilines are obtained in good yields. Despite the cationic intermediates of the electrolytic reaction tert-butyl moieties are tolerated.

Vielfältige elektrochemische C-H-Aminierung über Zincke-Zwischenstufen

Electrochemical instability of highly fluorinated tetraphenyl borates and syntheses of their respective biphenyls

Highly fluorinated tetraphenyl borate anions are of importance as weakly coordinating anions in metalorganic reactions. However, at high positive potentials their electrochemical stability in organic solvents is not sufficient. This was investigated by a comprehensive cyclic voltammetry study and can be used synthetically to generate highly fluorinated biphenyls.

Versatile Electrochemical C-H Amination via Zincke Intermediates.

Simply by applying electricity, the amination reaction of a broad variety of arenes, heteroarenes, and benzylic substrates is achieved. Pyridine serves as the nitrogen source and the intermediate cationic species are well-protected from over-oxidation.

Anodic Formation of Aryl Mesylates through Dehydrogenative Coupling Reaction

Electrifying Organic Synthesis

Abstract The direct synthetic organic use of electricity is currently experiencing a renaissance. More synthetically oriented laboratories working in this area are exploiting both novel and more traditional concepts, paving the way to broader applications of this niche technology. As only electrons serve as reagents, the generation of reagent waste is efficiently avoided. Moreover, stoichiometric reagents can be regenerated and allow a transformation to be conducted in an electrocatalytic fashion. However, the application of electroorganic transformations is more than minimizing the waste footprint, it rather gives rise to inherently safe processes, reduces the number of steps of many synth…

CCDC 1545585: Experimental Crystal Structure Determination

Related Article: Sabine Möhle, Sebastian Herold, Frank Richter, Hartmut Nefzger, Siegfried R. Waldvogel|2017|ChemElectroChem|4|2196|doi:10.1002/celc.201700476