Highly enantioselective and cis-diastereoselective cyclopropanation of olefins catalyzed by ruthenium complexes of (iminophosphoranyl)ferrocenes

Chiral (iminophosphoranyl)ferrocenes (1 and 2) are highly efficient ligands to achieve high diastereoselectivity (up to 95/5 dr in favor of the cis-isomer) as well as enantioselectivity (up to 99% ee) in Ru-catalyzed asymmetric cyclopropanation of various olefins. Reversal in diastereoselectivity is found as a function of metal-to-ligand ratio in the reaction of styrene.