Copper Hydride-Catalyzed Tandem 1,4-Reduction/Alkylation Reactions
作者:Bruce H. Lipshutz、Will Chrisman、Kevin Noson、Patrick Papa、Joseph A. Sclafani、Randall W. Vivian、John M. Keith
DOI:10.1016/s0040-4020(00)00132-0
日期:2000.4
Exposure of an enone to a catalytic quantity of [CuH(PPh3)]6 in the presence of one of several silyl hydrides (PhMe2SiH, PMHS, HMe2SiOSiMe2H) leads to conjugate reduction with concomitant formation of the corresponding silyl enolether. Without isolation, treatment of these intermediates with a Lewis acid at low temperatures in the presence of an aldehyde, or with fluoride ion together with an activated
[Rh(OH)(cod)]2 (cod = 1,5-Cyclooctadiene): A Highly Efficient Catalyst for 1,4-Hydrosilylation of α,β-Unsaturated Carbonyl Compounds
作者:Atsunori Mori、Tsuyoshi Kato
DOI:10.1055/s-2002-32609
日期:——
[Rh(OH)(cod)]2 (cod: 1,5-cyclooctadiene) is found to be a highly efficient catalyst for 1,4-hydrosilylation of α,β-unsaturated carbonyl compounds leading to enolsilanes. The reaction of 2-cyclohexen-1-one with HSiMe(OEt)2 in the presence of 0.005 mol% of the catalyst without solvent furnishes the corresponding enolsilane in 97% yield at room temperature within 10 min.
The use of dirhodium(II) catalysts in the 1,4-hydrosilylation of alpha,beta-unsaturated ketones and aldehydes was explored. Dirhodium(II) tetrakis(perfluorobutyrate), Rh2(pfb)4, proved to be the catalyst of choice for this process, providing the corresponding silyl enol ethers in high yields.
Nanoparticulate intermetallic compound Ni3Ga supported on SiO2 has emerged as a highly efficient catalyst for the hydrosilylation of carbonyls, such as aldehydes and ketones, at room temperature.
found that dehydrogenative silylation of ketones with hydrosilanes proceeds in the presence of a transition metal catalyst such as palladium on carbon or iridium carbonyl, with amine and halide as cocatalysts, to give the corresponding silylenolethers in good yields. The present reaction is applicable for a variety of ketones and hydrosilanes with complete regioselectivity.