Gold(I)-Catalyzed Conia-Ene Reaction of β-Ketoesters with Alkynes
Joshua J. Kennedy-Smith, Steven T. Staben and F. Dean Toste*
*Department of Chemistry, University of California, Berkeley, California 94720, Email: fdtosteberkeley.edu
J. J. Kennedy-Smith, S. T. Staben, F. D. Toste, J. Am. Chem. Soc., 2004, 126, 4526-4527.
DOI: 10.1021/ja049487s (free Supporting Information)
An intramolecular addition of β-ketoesters to unactivated alkynes under neutral conditions and at room temperature employs triphenylphosphinegold(I) cation as a catalyst. exo-Methylenecyclopentanes and cyclohexanes can be formed in excellent yields and with good diastereoselectivity.
see article for more examples
labeling experiments supporting a mechanism involving enol addition to a Au-alkyne complex (mechanism A)
B. K. Corkey, F. D. Toste, J. Am. Chem. Soc., 2005, 127, 17168-17169.