Intramolecular [4 + 2] Cycloadditions of 1,3-Enynes or Arylalkynes with Alkenes with Highly Reactive Cationic Phosphine Au(I) Complexes
摘要:
New Au(I) complexes with bulky, biphenyl phosphines are the most reactive catalysts for the cyclizations of enynes. 1,6-Enynes with an aryl ring at the alkyne give 2,3,9,9a-tetrahydro-1H-cyclopenta[b]naphthalenes by a 5-exo-dig cyclization followed by a Nazarov-type ring expansion. 1,8-Dien-3-ynes also cyclize by a 5-exo-dig pathway to form hydrindanes.
Gold(I)-Catalyzed Intermolecular Addition of Carbon Nucleophiles to 1,5- and 1,6-Enynes
作者:Catelijne H. M. Amijs、Verónica López-Carrillo、Mihai Raducan、Patricia Pérez-Galán、Catalina Ferrer、Antonio M. Echavarren
DOI:10.1021/jo8014769
日期:2008.10.3
Gold(I)-catalyzed addition of carbon nucleophiles to 1,6-enynes gives two different type of products by reaction at the cyclopropane or at the carbene carbons of the intermediate cyclopropyl gold carbenes. The 5-exo-dig cyclization is followed by most 1,6-enynes, although those bearing internal alkynes and alkenes react by the 6-endo-dig pathway. The cyclopropane versus carbene site-selectivity can
Enantioselective Folding of Enynes by Gold(I) Catalysts with a Remote <i>C</i><sub>2</sub>-Chiral Element
作者:Giuseppe Zuccarello、Joan G. Mayans、Imma Escofet、Dagmar Scharnagel、Mariia S. Kirillova、Alba H. Pérez-Jimeno、Pilar Calleja、Jordan R. Boothe、Antonio M. Echavarren
DOI:10.1021/jacs.9b06326
日期:2019.7.31
Chiral gold(I) catalysts have been designed based on a modified JohnPhos ligand with a distal C2-2,5-diarylpyrrolidine that creates a tight binding cavity. The C2-chiral element is close to where the C-C bond formation takes place in cyclizations of 1,6-enynes. These chiral mononuclear catalysts have been applied for the enantioselective 5-exo-dig and 6-endo-dig cyclization of different 1,6-enynes