Highly stereoselective synthesis of cyclopropylphosphonates catalyzed by chiral Ru(II)-Pheox complex.

Ru(II)-Pheox-catalyzed asymmetric cyclopropanation of diethyl diazomethylphosphonate with alkenes, including α,β-unsaturated carbonyl compounds, afforded the corresponding optically active cyclopropylphosphonates in high yields and with excellent diastereoselectivity (up to 99:1) and enantioselectivity (up to 99% ee).