Hydrosilation and Hydrometalations

/)-Me-CsH4, n-CsH, n-C g, HOCH2, HOCH2CH2, PhCH2, 1-naphthalenyl, CH2=CHCH20CH2, PhCH20CH2 

Subsequently, cationic rhodium catalysts are also found to be effective for the regio- and stereoselective hydrosilation of alkynes in aqueous media. Recently, Oshima et al. reported a rhodium-catalyzed hydrosilylation of alkynes in an aqueous micellar system. A combination of [RhCl(nbd)]2 and ( /5-(diphenylphosphino)propane (dppp) were shown to be effective for the ( )-selective hydrosilation in the presence of sodium dodecylsulfate (SDS), an anionic surfactant, in water. An anionic surfactant is essential for this ( )-selective hydrosilation, possibly because anionic micelles are helpful for the formation of a cationic rhodium species via dissociation of the Rh-Cl bond. For example, Triton X-100, a neutral surfactant, gave nonstereoselective hydrosilation whereas methyltrioctylammonium chloride, a cationic surfactant, resulted in none of the hydrosilation products. It was also found that the selectivity can be switched from to Z in the presence of sodium iodide (Eq. 4.47). 

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