Chelating diiminophosphorane and tripodal iminophosphorane copper and palladium complexes are found to efficiently catalyze the cyclopropanation of activated monosubstituted olefins with ethyl diazoacetate. Cycloolefins, and linear α-olefins are somewhat less reactive. The diastereoselectivities of the reactions are moderate and no major differences were seen when comparing the bidentate chelating ligand to the ...