Electrochemical conversion of fatty acids

Abstract

Electrochemical conversions combine an electron transfer with a chemical reaction, which allows conversions that are not available in non-electrochemical reactions. Electrochemical conversions usually need fewer steps, produce less waste, provide a cheaper reagent, require less auxiliaries, and allow often an easier scale-up than non-electrochemical syntheses. In addition, they can be conducted at ambient temperature and pressure. All these qualities agree well with the rules of green chemistry. Electroactive sites for fatty acids are the carboxyl group, the C-C double bond and the activated C-H bond. The deprotonated carboxyl group is anodically decarboxylated to afford an alkyl radical. The radical can couple or add to a C-C double bond. Radical coupling provides diesters, pheromones, or C-glycosides. At the anode the double bond can be substituted in allylic position, add two nucleophiles or can be cleaved. Cathodic reduction of fatty acids with an enone group affords dimer fatty acids in a hydrodimerization. Non-activated C-H bonds in fatty acids can be oxygenated at the anode; the conversion occurs preferentially at the remote C-H bonds.

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

“…Development and applications of Kolbe electrolysis before 2000 have been reviewed; 31,33,52 more recently, this classical process has been utilized to synthesize benzathine, 53 construct bis -phosphine oxide ligands, 54 and dimerize silylacetic acids 55–57 and fatty acids. 58 The mixed-Kolbe reaction, wherein a heterodimerization between two different alkyl carboxylic acids occurs, is less common—an excess of one acid component is often necessary to favor the cross-coupling product. 59 Renaud and co-workers applied a mixed-Kolbe electrolysis to synthesize nephromopsinic, phaseolinic, and dihydropertusaric acids (Figure 2A).…”

Elektrifizierung der organischen Synthese

“…[64] With regards to the conversion of fatty acids as renewables,amore recent article exists. [65] In general, present-day research on Kolbe electrolysis focuses on the generation of large-scale products such as biofuels [66] or adiponitrile. [67] In the following, we will highlight some contributions that represent synthetically relevant developments of the Kolbe electrolysis.…”

Moderne Aspekte der Elektrochemie zur Synthese hochwertiger organischer Produkte

“…Elektroaktive Bereiche der Fettsäuren sind dabei die Carboxygruppe,C-C-Doppelbindungen und aktivierte C-H-Bindungen. [117] Pentadecandisäuredimethylester wurde elektro-Schema 27. Diese Reaktion ist besser bekannt als Kolbe-Elektrolyse.H ohe Stromdichten und Wasserstoffatome in a-Position begünstigen die Radikalbildung.A us diesem Grund ist die Kolbe-Elektrolyse die bevorzugte Methode zur Umwandlung von Fettsäuren.…”