(Me3Si)3SiH was used as a successful reagent in a variety of radical-based transformations in water. The system comprising substrate, silane, and initiator (ACCN) mixed in aqueous medium at 100 degrees C worked well for both hydrophilic and hydrophobic substrates, with the only variation that an amphiphilic thiol was also needed in case of the water-soluble compounds.

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 solvent-soluble and water-soluble substrates. Different initiation methods to accomplish the radical-induced hydrosilylation reaction of C−C multiple bonds in water with (Me3Si)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 HOCH2CH2SH was also needed in the case of the water-soluble 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 radical-based methodologies studied in water are confronted.

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Reduction O 0220Radical Reactions in Aqueous Medium Using (Me3Si)3SiH. -Two methods for the title reactions are developed, depending on the hydrophilic or hydrophobic character of the substrates. Water-soluble substrates are dehalogenated [cf. (II)], decarbonylated [cf. (IV)], deoxygenated [cf. (VI)] or hydrosilylated [cf. (XVII)-(XXII)] using ACN as a radical initiator in catalytic amounts. The water-soluble substrates require 2-mercaptoethanol as an additional catalyst. Dehalogenation reaction is applied to a variety of ribose-derived bromides and iodides [cf. (XII)]. Various azides are transferred to the corresponding amines [cf. (XIV)]. -(POSTIGO, A.; KOPSOV, S.; FERRERI, C.; CHATGILLIALOGLU*, C.; Org. Lett. 9 (2007) 25, 5159-5162; Cons. Naz. Ric., Ist. Sin. Org. Fotoreatt., CNR, I-40129 Bologna, Italy; Eng.) -R. Steudel 18-038