Silylcarbonylation of Vinylsilanes Catalyzed by Iridium(I) Siloxide Complexes

The iridium siloxide complexes [{Ir(μ-OSiMe3)(cod)}2] (I) and [Ir(cod)(PCy3)(OSiMe3)] (II) were used as catalysts in the silylcarbonylation of CH2CHSiMe3. While complex I effectively catalyzed the highly stereoselective formation of (E)-1-(dimethylphenylsiloxy)-1-(dimethylphenylsilyl)-3-(trimethylsilyl)-1-propene (1a, Me3SiCH2CHC(OSiMe2Ph)SiMe2Ph; yield 82%), complex II led the reaction to stereoselective synthesis of (Z)-1-(dimethylphenylsiloxy)-3-(trimethylsilyl)-1-propene (2a, Me3SiCH2CHCHOSiMe2Ph; yield 95%). The former product was used for synthesis of the acylsilane (Me3SiCH2CH2C(O)SiMe2Ph) (4a; yield 92%), a well-known reagent in organic synthesis. Under a CO atmosphere the cyclooctadiene ligand in both complexes was replaced by CO, and the X-ray structure of [Ir(CO)2(PCy3)OSiMe3] (IV) was resolved.