Hydrosilylation of C-C multiple bonds using (Me3Si) 3SiH in water: Comparative study of the radical initiation step

Abstract

The classical radical-based hydrosilylation reaction of organic compounds bearing C-C multiple bonds is usually carried out in organic solvents and is herein presented in water with both organic solventsoluble and water-soluble substrates. Different initiation methods to accomplish the radical-induced hydrosilylation reaction of C-C multiple bonds in water with (Me 3Si)3SiH are presented. In the thermal decomposition of azo compounds, the system comprising substrate, silane, and azo-initiator (ACCN) mixed in aqueous medium at 100 °C worked well for both hydrophilic and hydrophobic substrates, with the only variation that the amphiphilic thiol HOCH2CH3SH was also needed in the case of the watersoluble compounds. Dioxygen initiation is shown to afford excellent yields of hydrosilylated products derived from substrates bearing C-C triple bonds and moderate to low yields of hydrosilylated products derived from C-C double-bonded compounds in water. Photochemical initiation in the absence of a chemical radical precursor other than the silane is also found to be a very efficient and convenient method to induce the hydrosilylation reaction of both C-C double and triple bonds of organic compounds (hydrophilic and hydrophobic substrates) with (Me3Si)3SiH in water. These three alternative radicalbased methodologies studied in water are confronted.