The strongly increasing demand for nano-and microelectronics calls for new and environmentally benign reaction pathways for the preparation of one of the most important substrates in the production of semiconductor materials: Si 2 Cl 6 . We present a comprehensive study of the opportunities and challenges for the selective electrochemical formation of higher halo-functionalized silanes to Si 2 Cl 6 achieved by cyclic voltammetry measurements and electrochemical synthesis. Cathodic dehalo-dimeriza-tion reaction of SiCl 4 and the approach to halogen exchange for better substrate reduction are envisioned. An anodic halide-free dimerization pathway by dehydrogenation of HSiCl 3 is investigated, including Lewis acid activation of the SiÀ H bond. In addition, tertiary amine-driven, Benkeser-like in-situ formation of a SiCl 3 À anion was tested as well. The target molecule Si 2 Cl 6 is strongly promoted to direct electro-conversions making the anodic and cathodic electrosynthesis very challenging.

Organosilanes play an important role in organic synthesis as well as in a variety of further areas, ranging from life science to transportation. Especially, the electrochemical access has become increasingly important in the past years and developed into an essential topic due to new conceptual approaches and mediated reaction control. With the commercial availability of high‐quality electrochemical equipment, the technical requirements for electro‐conversion are at hand to a wide audience. This results in the need for a concise survey of electrochemical silane transformation, appropriate for novices as well as experts alike. This review provides an overview of the most relevant work in this field, identifies common obstacles in working with chlorosilanes and hydrosilanes and bridges the gap between known techniques and novel methods with respect to their electrochemical conversion. The historical development is outlined with reference to the various cathodic as well as anodic conversions and should encourage to expand the research field of electrochemical silane transformation.

The range of possible applications of B(C6F5)3 extends into many areas of organic and inorganic chemistry. However, electrochemical synthesis with hydrosilanes using B(C6F5)3 to increase yield or scope has not yet been achieved. A comprehensive study on the use of Lewis acidic boron species, especially B(C6F5)3, for the activation of hydrosilanes in presence of commercially available supporting electrolyte for Si−C bond formation was presented. The benzylation and allylation of hydrosilane species was successfully conducted in presence of catalytic amounts of B(C6F5)3 in yields up to 86 %. Screening of electrode materials revealed leaded bronzes as superior for cathodic conversion without contamination of the electrolyte by heavy metals. Supported by cyclic voltammetry studies, B(C6F5)3 activated the hydrosilane for easier nucleophilic access, leading to significant increase in yield and enrichment of the target product in the reaction mixture.

We successfully achieved methylation of various SiO2 sources to cyclic methylsiloxanes via electroreduction reaction. Contrary to previous assumptions, the reaction does not start from methanol as methyl radical source, that results in methoxylation of the electrolyte solvent. Methylammonium cations were found to enable the direct conversion, strongly dependent on the radical intermediate stabilization by the electrolyte. THF/Bu4NCF3SO3 is the sole applicable system with yields below 14 % referred to the methylammonium cations for the highest amount of product obtained so far. Mechanistic insights show that methylation does not occur via the supposed hydrolysis of dimethoxydimethylsilane intermediate, but via a direct conversion reaction, as comparative studies of a Fenton‐type procedure clearly indicate. Further, cyclic methylsiloxane products are prone to subsequent electrochemical equilibration, strongly directed by the electrolyte solvent.