Design and Synthesis of a Chiral N-Tethered Bis(imidazoline) Ligand

A chiral nitrogen-tethered bis (imidazoline) ligand (Nb-imidazoline) was newly designed and synthesized in a divergent strategy. Thus, a single coupling reaction of primary amine with two molecules of chloromethylated imidazoline provided the Nb-imidazoline. The copper(II) triflate complex of Nb-imidazoline catalyzed a trans-selective cyclopropanation of styrene with ethyl diazoacetate to give the adduct in high chemical yield with good enantiomeric excess up to 83%.