Copper(I)-imine complexes: Synthesis and catalytic activity in olefin cyclopropanation
作者:G. Attilio Ardizzoia、Stefano Brenna、Fulvio Castelli、Simona Galli
DOI:10.1016/j.ica.2009.03.038
日期:2009.8
Different imine-type ligands, prepared by the condensation of anilines or of alpha-methylbenzylamine with 2-pyridinecarboxaldehyde (pyim(1,2)) or 2-quinolinecarboxaldehyde (quim(1,2)) were prepared. These species act as N,N'-bidentate, chelating ligands upon coordination to Cu(I): treatment of [Cu(PPh3)(3)Cl] with an equimolar amount of the ligands resulted in the displacement of two molecules of PPh3, giving rise to the formation of [Cu(pyim(1,2))(PPh3)Cl] (1-2) and [Cu(quim(1,2))(PPh3)Cl] (3-4), respectively. The copper derivatives 1-4 proved to be highly active catalysts in olefin cyclopropanation in the presence of ethyl diazoacetate, even using deactivated olefins (namely, 2-cyclohexen-1-one) as substrate. The X-ray structure of complex 2, [Cu(pyim(2))(PPh3)Cl], is also reported. (C) 2009 Elsevier B.V. All rights reserved.