Optically active N, N′-ethylenebis (α-alkoxycarbonyl-β-ketoimine) was found to be a new class of effective ligand of manganese (III) complex catalyst for the asymmetric aerobic epoxidation of simple olefins, such as 1, 2-dihydronaphthalene derivatives, to afford the corresponding optically active epoxides with good to high enantioselectivities.