857722-54-4Relevant academic research and scientific papers
Intramolecular hydroarylation of alkynes catalyzed by platinum or gold: Mechanism and endo selectivity
Nevado, Cristina,Echavarren, Antonio M.
, p. 3155 - 3164 (2005)
The cyclization of differently substituted aryl alkynes with Pt II or AuI catalysts proceeds by endo-dig pathways. When AgI was used to generate reactive cationic AuI catalysts, 2H-chromenes dimerize to form cyclobutane derivatives by a Ag I-catalyzed process. A DFT study on the cycliza-tion mechanism shows a kinetic and thermodynamic preference for 6-endodig versus 5-exo-dig cyclizations in PtII-catalyzed processes. Calculations indicate that although Friedel-Crafts and the cyclopropanation processes via metal cyclopropyl carbenes show very similar activation energies, platinum cyclopropyl carbenes are the stationary points with the lowest energy.
