Ni(II)-Catalyzed Conia-Ene Reaction of 1,3-Dicarbonyl Compounds with Alkynes
作者:Qiang Gao、Bao-Fu Zheng、Jin-Heng Li、Dan Yang
DOI:10.1021/ol050532q
日期:2005.5.1
We have discovered a Ni(II)-catalyzed Conia-ene reaction of 1,3-dicarbonyl compounds with alkynes. In the presence of Ni(acac)(2) and Yb(OTf)(3), various acetylenic 1,3-dicarbonyl compounds underwent Conia-ene reaction to give mono- and bicyclic olefinic cyclopentanes. A mechanism involving the enol-yne-Ni complex formation is proposed and supported by deuterium-labeling experiments.
Gold(I)-Catalyzed Conia-Ene Reaction of β-Ketoesters with Alkynes
作者:Joshua J. Kennedy-Smith、Steven T. Staben、F. Dean Toste
DOI:10.1021/ja049487s
日期:2004.4.1
The intramolecular addition of beta-ketoesters to unactivated alkynes under neutral conditions and at room temperature is described. The method employs triphenylphosphinegold(I) cation as a catalyst for the formation of exo-methylenecycloalkanes. Both monocyclic and bicyclic cyclopentanes and cyclohexanes can be formed in excellent yields and with good diastereoselectivity.
Synthetic Usefulness of the Cobalt(I)-Mediated Ene Type Reaction for the Diastereoselective Construction of Bicyclo[n.3.0]derivatives
Cobalt(I)-catalyzed cycloisomerization of cyclic â-acetylenic β-ketoesters 1 led to bicyclo[n.3.0]derivatives 2 in high yield and with a total stereocontrol of two contiguous centers.
N′-disubstituted cyclic thioureas as ligands for gold(I) catalysis. X-ray crystal structures of the thiourea-gold(I) complexes presented important information about the nature of the complexation. These complexes were found to be active catalysts for the cyclization of 1,3-dicarbonylcompounds with alkynes (Conia-ene reaction). Various acetylenic 1,3-dicarbonylcompounds underwent cycloisomerization to give mono-