Intramolecular Hydroarylation of Alkynes Catalyzed by Platinum or Gold: Mechanism andendo Selectivity
作者:Cristina Nevado、Antonio M. Echavarren
DOI:10.1002/chem.200401069
日期:2005.1
The cyclization of differently substituted aryl alkynes with PtII 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 AgI-catalyzed process. A DFT study on the cyclization mechanism shows a kinetic and thermodynamic preference for 6-endo-dig versus 5-exo-dig cyclizations in PtII-catalyzed
Phosphine Gold(I) Bis-(trifluoromethanesulfonyl)imidate Complexes as New Highly Efficient and Air-Stable Catalysts for the Cycloisomerization of Enynes
作者:Nicolas Mézailles、Louis Ricard、Fabien Gagosz
DOI:10.1021/ol0515917
日期:2005.9.1
[reaction: see text] A study concerning the synthesis of new phosphine gold(I) complexes using the bis(trifluoromethanesulfonyl)imidate moiety as a weakly coordinating counter-anion is described. These new air-stable complexes are more convenient to prepare, store, and handle and are exceedingly active for the catalysis of a wide range of enynes cycloisomerizations.