Hydrosilylation of Allenes Over Palladium-Gold Alloy Catalysts: Enhancing Activity and Switching Selectivity by the Incorporation of Palladium into Gold Nanoparticles
route to alkenylsilnaes involving hydrosilylation of allenes by supported palladium-gold alloy catalysts has been developed. The catalytic activity and the product selectivity were drastically changed by the incorporation of palladium atoms into goldnanoparticles (NPs). The supported Pd-Au alloy catalysts with a low Pd/Au ratio were highly effective for the hydrosilylation at ambient temperature, in which
The synthesis of four oligo ethylene glycol substituted, bis-NHC palladium(II) and platinum(II) complexes is reported. Two of them were characterized by solid state structures. All complexes show excellent solubility in a variety of organic solvents and water. The palladiumcomplexes were tested in the Suzuki–Miyauracouplingreaction and the platinum complexes in the hydrosilylation reaction of alkynes
Catalytic hydrosilylation of acetylenes mediated by phosphine complexes of cobalt(I), rhodium(I), and iridium(I)
作者:Leslie D. Field、Antony J. Ward
DOI:10.1016/s0022-328x(03)00582-5
日期:2003.9
The complexes [Co(PPh3)3Cl] (1), [Co(PPh3)2(CO)2Cl] (2), [Co(PMe3)3Cl] (3), [Co(PMe3)2(CO)2Cl] (4), [Rh(dppe)(CO)Cl] (5), [Rh(PPh2Me)2(CO)Cl] (6), [Ir(dppe)(CO)Br] (7), and [Ir(PPh2Me)2(CO)Cl] (8) catalyse the hydrosilylation of a range of acetylenes including 1-hexyne, phenylacetylene, and 1-phenyl-1-propyne with triethylsilane. In the case of 1-hexyne and 1-phenyl-1-propyne, only the expected hydrosilylation
Lewis acids such as AlCl3 or EtAlCl2 dramatically catalyzed the hydrosilylation of alkynes 1 with trialkylsilanes to produce the corresponding cis-vinylsilanes 2 in a regio- and trans-stereoselective manner. For example, the hydrosilylation of 1-dodecyne la with triethylsilane in the presence of 0.2 equiv of AlCl3 gave cis-1-(triethylsilyl)-1-dodecene in 93% yield. Other alkyl- and phenyl-substituted terminal and internal acetylenes also underwent trans-hydrosilylation very smoothly. In the case of alkoxy- or silyloxy-substituted acetylenes, the use of 1.2 equiv of AlCl3 or EtAlCl2 was essential to obtain the corresponding trans-hydrosilylation products in high yields. Moreover, AlCl3 catalyzed the hydrosilylation of aromatic allenes 11, producing the alkenylsilanes 12 with high regio- and stereoselectivities in moderate to high chemical yields. Not only the simple monosubstituted, but also the disubstituted and trisubstituted allenes, underwent the hydrosilylation reaction smoothly, serving as a useful tool for the synthesis of differently substituted vinylsilanes which are not easily available through the previously known methodologies. The mechanisms for these catalytic reactions of alkynes and allenes are proposed.
Lewis Acid-Catalyzed <i>trans</i>-Hydrosilylation of Alkynes