A new chiral ruthenium complex for catalytic asymmetric cyclopropanation

A new chiral ruthenium complex 6, featured with an N,O-mixed polydentate ligand, was synthesized and characterized. This ruthenium complex showed high efficiency in catalytic cyclopropanations of alkenes with diazoacetates. High trans/cis selectivity and enantioselectivity (up to 96%) were achieved with the readily accessible ethyl diazoacetate as the reagent.