New bis(1-ferrocenylethyl)amine-derived monodentate phosphoramidite ligands for highly enantioselective copper-catalyzed 1,4-conjugate addition

Abstract

A new family of chiral bis(1-ferrocenylethyl)amine-derived monodentate phosphoramidite ligands has been prepared and successfully applied in the Cu-catalyzed asymmetric 1,4-conjugate addition of diethylzinc to a variety of α,β-unsaturated compounds, in which up to 99% ee was obtained for nitroalkenes at -78 °C and >98% ee for cyclohexenone at -30 °C, comparable to or higher than those obtained with the most efficient monophosphoramidite ligands reported so far. © 2009 Elsevier Ltd. All rights reserved.