Homogeneous electro-mediated reduction of unsaturated compounds using Ni and Fe as mediators in DMF

Electrochemical chemoselective hydrogenation of 1,4-enediones with HFIP as the hydrogen donor: scalable access to 1,4-diketones

A straightforward electrochemical protocol for efficient hydrogenation of unsaturated CC bonds has been reported in an undivided cell. A series of versatile 1,4-diketones are smoothly generated under metal-free and external-reductant-free electrolytic conditions. Moreover, the tolerance of various functional groups and decagram-scale experiments have shown the practicability and potential applications of this methodology. Moreover, a range of heterocyclic compounds were easily prepared through follow-up procedures of 1,4-diketones.

Electro-Synthesis of Organic Compounds with Heterogeneous Catalysis

Electro-organic synthesis has attracted a lot of attention in pharmaceutical science, medicinal chemistry, and future industrial applications in energy storage and conversion. To date, there has not been a detailed review on electro-organic synthesis with the strategy of heterogeneous catalysis. In this review, the most recent advances in synthesizing value-added chemicals by heterogeneous catalysis are summarized. An overview of electrocatalytic oxidation and reduction processes as well as paired electrocatalysis is provided, and the anodic oxidation of alcohols (monohydric and polyhydric), aldehydes, and amines are discussed. This review also provides in-depth insight into the cathodic reduction of carboxylates, carbon dioxide, CC, C≡C, and reductive coupling reactions. Moreover, the electrocatalytic paired electro-synthesis methods, including parallel paired, sequential divergent paired, and convergent paired electrolysis, are summarized. Additionally, the strategies developed to achieve high electrosynthesis efficiency and the associated challenges are also addressed. It is believed that electro-organic synthesis is a promising direction of organic electrochemistry, offering numerous opportunities to develop new organic reaction methods.

Electrocatalysis with Molecular Transition-Metal Complexes for Reductive Organic Synthesis

Electrocatalysis enables the formation or cleavage of chemical bonds by a genuine use of electrons or holes from an electrical energy input. As such, electrocatalysis offers resource-economical alternative pathways that bypass sacrificial, waste-generating reagents often required in classical thermal redox reactions. In this Perspective, we showcase the exploitation of molecular electrocatalysts for electrosynthesis, in particular for reductive conversion of organic substrates. Selected case studies illustrate that efficient molecular electrocatalysts not only are appropriate redox shuttles but also embrace the features of organometallic catalysis to facilitate and control chemical steps. From these examples, guidelines are proposed for the design of molecular electrocatalysts suited to the reduction of organic substrates. We finally expose opportunities brought by catalyzed electrosynthesis to functionalize organic backbones, namely using sustainable building blocks.

Chemoselective Electrochemical Hydrogenation of Ketones and Aldehydes with a Well-Defined Base-Metal Catalyst

Hydrogenation reactions are fundamental functional group transformations in chemical synthesis. Here, we introduce an electrochemical method for the hydrogenation of ketones and aldehydes by in situ formation of a Mn-H species. We utilise protons and electric current as surrogate for H2 and a base-metal complex to form selectively the alcohols. The method is chemoselective for the hydrogenation of C=O bonds over C=C bonds. Mechanistic studies revealed initial 3 e- reduction of the catalyst forming the steady state species [Mn2 (H-1 L)(CO)6 ]- . Subsequently, we assume protonation, reduction and internal proton shift forming the hydride species. Finally, the transfer of the hydride and a proton to the ketone yields the alcohol and the steady state species is regenerated via reduction. The interplay of two manganese centres and the internal proton relay represent the key features for ketone and aldehyde reduction as the respective mononuclear complex and the complex without the proton relay are barely active.

Electrochemical reduction of functionalized carbonyl compounds: enhanced reactivity over tailored nanoporous gold

The effect of the pore size of nanoporous gold on electrochemical reduction of functionalized carbonyl compounds was investigated. NPG with a pore size of ∼30 nm significantly enhanced the reactivity with high chemo-selectivity at a low-potential. Typically, p-nitrobenzaldehyde reduction demonstrates a high turnover frequency (TOF) up to 232 000 h-1.

Electrochemical quantification of piperine in black pepper

A simple, rapid method of the detection of piperine in black pepper is reported using a voltammetric sensor based on a glassy carbon (GC) electrode with analysis following a short one-step extraction using ethanol. The method is based on a novel potential sweep designed to maximise signal sizes and shown with context of the present analytical challenge to be essential for gathering data allowing the construction of a linear calibration curve for the analysis in the relevant range namely 0.25-5.0 mM.

Electrochemical 1,4-reduction of α,β-unsaturated ketones with methanol and ammonium chloride as hydrogen sources

This protocol presented a sustainable, chemoselective 1,4-reduction of α,β-unsaturated ketones by means of an electrochemical method with ammonium chloride (NH₄Cl) as the only additive.

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

Electrochemistry represents one of the most intimate ways of interacting with molecules. This review discusses advances in synthetic organic electrochemistry since 2000. Enabling methods and synthetic applications are analyzed alongside innate advantages as well as future challenges of electroorganic chemistry.