Chiral ruthenium catalysts comprising salen and alkenyl ligands are provided for stereoselective cyclopropanation, and methods of cyclopropanation are provided. The chiral ruthenium catalyst is prepared in situ by combining an alkenyl ligand, a deprotonated chiral salen ligand, and a ruthenium (II) metal. A preferred catalyst is prepared in situ by combining 2,3-dihydro-4-venylbenzofuran, deprotonated 1,2-cyclohexanediamino-N,N′-bis(3,5-di-t-butyl-salicylidene) and RuCl2(p-cymene)]2.