Silylcarbonylation of Alkenes and Alkynes

Iridium siloxide complexes show a similar activity. Catalytic tests performed in the presence of [ Ir( 4-OSiMe3)(cod) 2], with the use of trimethylvinylsilane and dimethylphenylsilane as reactants [59], gave the same type of silicon derivatives as those obtained by Murai and coworkers [58], but the siloxide iridium precursor used appeared to be more efficient under milder conditions. When the [Ir(cod)(PCy3)(OSiMe3)] was used rather than the binuclear iridium siloxide complex, Z-Me3SiCH2CH=CHOSiMe2Ph was obtained exclusively [59], 

The iridium cluster [Ir4(CO)i2], which was used successfully as an olefin silylcarbonylation catalyst, also appeared effective in the formation of nitrogen hetero- 

The binuclear precursor [ lr( 4-Cl)(cod) 2] has been also studied in the carbonyla-tive silylcarbocyclization of enynes occurring according to Equation 14.7  

The tests performed under various conditions showed only a moderate selectivity of the iridium complex in this process. Under optimized conditions (20 bar CO, 80°C, 18h) only 75% of the desired product (aldehyde) was obtained [61]. 

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