**1. Introduction**

The stereochemistry of organic compounds can dramatically influence their properties, such as biological activity of pharmaceuticals or macroscopic physical characteristics of polymers. Thus, the ability to control the stereochemical outcome in organic synthesis can be of grea<sup>t</sup> importance, and asymmetric catalysis is an indispensable tool in this endeavor. In asymmetric catalysis, racemic or prochiral substrates are converted to stereogenically enriched products with the aid of a chiral mediator in sub-stoichiometric amounts. As the catalyst is continually being reused in the process, the strategy presents grea<sup>t</sup> opportunities for highly atom-e fficient processes. Traditionally, asymmetric catalysis has focused on two-electron transformations [1,2]. However, the toolbox of the organic chemist has been expanded tremendously in the last decade with the introduction of methods for asymmetric transformations with open-shell radical intermediate species using chemical, photochemical and electrochemical strategies [3–10].

In electrosynthesis, chemical redox reagents are replaced with electricity for the transformation of organic molecules. While dating back to the 19th century, the topic is currently receiving renewed interest due to its enabling potential for selective and sustainable synthesis [11–19]. In an electrochemical reaction, oxidation occurs at the anode and reduction at the cathode in a conductive medium. The redox processes can take place at constant current or constant potential in an undivided or divided electrochemical cell, where the latter separates the anodic and cathodic compartments by a conductive membrane [20]. The redox event that ultimately converts starting material to product in electrosynthesis can occur via di fferent paths. As exemplified for a net-oxidative process, the electron transfer from a substrate to the anode can occur directly at the electrode surface (Figure 1a) or take place in solution with the aid of a homogeneous redox mediator. The latter represents indirect electrolysis (Figure 1b), where the mediator e ffectively acts as a catalyst for the electron transfer. The use of such redox mediators can facilitate the redox event from electrode to substrate and thereby reduce energy consumption and enable milder conditions with higher chemoselectivities [15,21]. In addition, electricity can be used to drive product formation by (re)generation of catalytically active species (Figure 1c). For clarity, we use the word "redox mediator" for electron transfer catalysts in this review, whereas "catalyst" denotes compounds added in catalytic amounts to mediate a transformation by other mechanistic action. In the context of asymmetric electrosynthesis, both redox mediators and catalysts can be chiral and induce stereoselectivity in the reaction in which they are used. Mechanistic insight can be crucial for rational development of new catalysts and synthetic protocols. To probe the reaction mechanism of electrosynthetic reactions, electroanalytical techniques such as cyclic voltammetry (CV) in combination with classic chemical approaches are commonly used [22].

**Figure 1.** Examples of electrosynthetic pathways for substrate oxidation (cathodic reaction not shown) (**a**) direct anodic oxidation; (**b**) indirect anodic oxidation; (**c**) indirect oxidation by anodic activation and regeneration of catalyst.

In this review, electrosynthetic protocols that utilize catalytic amounts of small organic or metal-based chiral mediators to afford asymmetric induction in C–H functionalization, alkene functionalization, carboxylation and cross-electrophile couplings are discussed, along with mechanistic aspects of the transformations. Other strategies for asymmetric electrosynthesis, e.g., biocatalysis, chiral auxiliaries, pre-functionalized chiral electrodes and chiral media have recently been covered elsewhere and will not be discussed here [3–6,23–25]. This review is divided into oxidative and reductive transformations and highlights recent developments up to July 2020.
