898267-60-2Relevant academic research and scientific papers
Gold- And platinum-catalyzed cycloisomerization of enynyl esters versus alleneyl esters: An experimental and theoretical study
Marion, Nicolas,Lemiere, Gilles,Correa, Andrea,Costabile, Chiara,Ramon, Ruben S.,Moreau, Xavier,De Fremont, Pierre,Dahmane, Rim,Hours, Alexandra,Lesage, Denis,Tabet, Jean-Claude,Goddard, Jean-Philippe,Gandon, Vincent,Cavallo, Luigi,Fensterbank, Louis,Malacria, Max,Nolan, Steven P.
experimental part, p. 3243 - 3260 (2010/06/12)
Experimental and theoretical studies on Au- and Pt-catalyzed cycloisomerization of a branched dienyne with an acetate group at the propargylic position are presented. The peculiar architecture of the dienyne precursor, which has both a 1,6- and a 1,5-enyne skeleton, leads, in the presence of alkynophilic gold catalysts, to mixtures of bicyclic compounds 3, 4, and 5. Formation of unprecedented bicyclo[3.1.0]hexene 5 is the main focus of this study. The effect of the ancillary ligand on the gold center was examined and found to be crucial for formation of 5. Further mechanistic studies, involving cyclization of an enantioenriched dienyne precursor, 18O-labeling experiments, and DFT calculations, allowed an unprecedented reaction pathway to be proposed. We show that bicyclo[3.1.0]hexene 5 is likely formed by a 1,3-OAc shift/allene-ene cyclization/ 1,2-OAc shift sequence, as calculated by DFT and supported by Au-catalyzed cyclization of isolated allenenyl acetate 7, which leads to improved selectivity in the formation of 5. Additionally, the possibility of OAc migration from allenyl acetates was supported by a trapping experiment with styrene that afforded the corresponding cyclopropane derivative. This unprecedented generation of a vinyl metal carbene from an allenyl ester supports a facile enynyl ester/allenenyl ester equilibrium. Further examination of the difference in reactivity between enynyl acetates and their corresponding [3,3]-rearranged allenenyl acetates toward Au- and Pt-catalyzed cycloisomerization is also presented.
Use of ionic liquids in the platinum- and gold-catalyzed cycloisomerization of enyne systems
Moreau, Xavier,Hours, Alexandra,Fensterbank, Louis,Goddard, Jean-Philippe,Malacria, Max,Thorimbert, Serge
experimental part, p. 561 - 565 (2009/06/05)
The platinum- and gold-catalyzed cycloisomerization of enyne systems has been carried out in various ionic liquids (ILs). In some cases, better selectivities and shorter reaction times have been observed compared to conventional conditions.
AuI-catalyzed cycloisomerization of 1,5-enynes bearing a propargylic acetate: Formation of unexpected bicyclo[3.1.0]hexene
Marion, Nicolas,De Fremont, Pierre,Lemiere, Gilles,Stevens, Edwin D.,Fensterbank, Louis,Malacria, Max,Nolan, Steven P.
, p. 2048 - 2050 (2008/09/18)
The use of N-heterocyclic carbene (NHC) as a ligand in the gold(i)-catalyzed cycloisomerization of enyne results in the assembly of a new carbocyclic product. The Royal Society of Chemistry 2006.
