Catalytic Synthesis of Silanols from Hydrosilanes and Applications

Abstract

In recent years reusable and highly active metal-nanoparticle catalysts were developed for the selective transformation of hydrosilanes into the corresponding silanols using water as the oxidant. The catalysts are much more active catalyst than conventional homogeneous ones under ambient conditions. In this perspective, we summarize known catalyst systems as well as stoichiometric methods for the synthesis of silanols from hydrosilanes. Plausible pathways for the hydrolytic oxidation of hydrosilanes on metal nanoparticles are described on the basis of the observations of mechanistic studies, including Si-H bond activation, nucleophilic attack of water (or silanol) at the silicon bonded to metal, and the liberation of silanol (or disiloxane) products. The applications of silanols are classified into usages in organic synthesis and silicon-based materials. Silanols were employed as nucleophilic partners in transition-metal catalyzed carbon-carbon cross-coupling reactions, organocatalysts for activating carbonyl compounds, intramolecular guiding groups for C-H bond activation reactions, inhibitors of enzymes, and isosteres of bioactive compounds. Various polymeric silicon-based materials were synthesized by the activation of Si-H bonds in bis-trihydrosilanes, bis-hydrosilanes, and polyhedral oligomeric silsesquioxanes (POSS).