Müller–Rochow Reloaded: Single-Step Synthesis of Bifunctional Monosilanes

A convenient single-step process is reported that provides efficient access to the most valuable bifunctional hydridochlorosilane Me2SiHCl from the crude Müller–Rochow product mixture. Conceptually, the unavailability of routes to the selective partial reduction of chlorosilanes has been circumvented by using in situ H/Cl exchange, employing substoichiometric amounts of LiH to produce fully reduced hydridosilanes that undergo immediate redistribution with the remaining chlorosilanes in a single step. The reaction is autocatalyzed by LiCl, but reaction temperatures are efficiently reduced in the presence of redistribution catalysts such as simple onium chlorides. Onium chlorides also act as efficient cleavage catalysts for disilanes and carbodisilanes present in the Müller–Rochow product mixture, conversion of which increases the hydridochlorosilane yield up to 58%. Making use of additional post-processing steps for the remaining byproducts, bifunctional monosilane yields exceeding 90% are possible.