Electrochemical Synthesis of Functional Organosilanes II: Direct Electrochemical Formation of Si-C Bonds

Electroreductive Si-C bond formation was used for the formation of organofunctional silanes of the general formula HMe2Si-R-Y and MeOMe2Si-R-Y (R = alkylene, arylene; Y = H, MeO, Me2N, t-BuMe2SiO). Employing constant current conditions, different organic halides R-X (R = alkylene, arylene, X = Cl, Br) were electrolyzed in the presence of Me2Si(OMe)2 and HMe2SiCl, respectively. All electrolyses were carried out in an undivided cell and with a THF/LiCl (MgCl2) electrolyte. Although both salts are suitable supporting electrolytes, the highest conductivity was obtained with a mixture of LiCl/MgCl2 = 2/1. It was shown that the reaction proceeds smoothly at current densities between 0.25 and 35 mA cm−2. Cooling of the electrolysis cell can be omitted.