Enantiocontrol in C-H insertion reactions of 3 degrees alkyl diazoacet
ates, which is highly dependent on the catalyst ligand, is greatly enh
anced with the use of dirhodium(II)tetrakis[methyl 1-acetylimidazolidi
n-2-one-4(S)-carboxylate], Rh-2(4S-MACIM)(4).