The large-scale synthesis with greatly improved yields of methyl 1-(3-phenylpropanoyl)-2- oxaimidazolidine-4 (S)-carboxylate and the chiral dirhodium (II) carboxamidate derived from it, Rh2 (4S-MPPIM) 4, is described. The key step in the overall synthesis is the Hofmann rearrangement of Boc-protected l-asparagine, the procedure for which has been modified to achieve near quantitative yield.
