Aryl- and alkenylsilanediols, which possess two hydroxy groups on the silicon atom, undergo the rhodium-catalyzed addition of an organic group on silicon to internal alkynes. Treatment of several internal alkynes with aryl- or alkenylsilanediols in the presence of 3 mol% of [Rh(OH)(cod)]2 affords the hydroarylated or hydroalkenylated products in good yields. A crucial role of the hydroxy group of silanediol for the catalytic reaction is also discussed with the related aryltin reagent.
Palladium-catalyzed cross-coupling of aryl- or alkenylsilanols, silanediols, and silanetriols with a variety of iodoarenes by the catalysis of palladium(0) and in the presence of silver(I) oxide furnished the coupling products in good to excellent yields. The reactions of silanediols or silanetriols under similar conditions proceeded much faster than those of silanols to afford the corresponding coupling
Arylation and alkenylation of aromatic aldehydes with silanediols is shown to proceed by use of a catalytic amount of rhodium complex. Treatment of ethyl(4-methoxyphenyl)silanediol with benzaldehyde in the presence of 3 mol% of [Rh(OH)(cod)]2 affords 4-methoxyphenyl(phenyl)methanol in 59% yield after stirring at 70 °C for 24 hours. On the other hand, diarylketone was also obtained at elevated temperature via β-hydride elimination from intermediary rhodium alkoxide.