Copper-catalyzed asymmetric conjugate addition of diethylzinc to chalcones could be realized by using [2.2]paracyclophane-derived monodentate phosphoramidite ligands. The excellent yield and enantioselectivity (up to 98% yield and 95% enantiomeric excess) could be realized with low catalyst loading of 1.0 mol % and low ligand loading of 1.2%.
Han L,Lei Y,Xing P,et al. [2.2]Paracyclophane-Derived Monodentate Phosphoramidite Ligands for Copper-Catalyzed Asymmetric Conjugate Addition of Diethylzinc to Substituted Chalcones[J]. J. Org. Chem.,2015,80(8):3752-3757.