Chiral dinuclear phthalazine bridged bisoxazoline ligands: synthesis and application in enantioselective Cu-catalyzed conjugate addition of ZnEt2 to enones

A new class of chiral dinuclear ligands with phthalazine bridged bisoxazoline scaffold was designed and prepared in convenient synthetic routes. 1H NMR analysis showed that this class of ligands could coordinate with two metal ions, either same or different. These ligands afforded good to excellent yields and enantioselectivities in Cu-catalyzed conjugate addition of ZnEt2 to enones.