Boron-catalyzed electrochemical Si−C bond formation for safe and controllable benzylation and allylation of hydrosilanes

Abstract

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.