Catalyzed addition of diazoacetoacetates to imines: synthesis of highly functionalized aziridines.

The addition of diazoacetoacetates to aromatic imines derived from p-methoxyaniline is achieved using dirhodium tetraacetate as the catalyst. Highly functionalized aziridines are obtained in good yield and with excellent stereoselectivity. 2-Diazo-1,3-diketones also provide good yields of aziridines, but dimethyl diazomalonate is inactive in the transformation. The diazoacetoacetates of chiral alcohols are also examined in the reaction and moderate diastereoselectivity is achieved with (R)-pantolactone-derived diazoacetoacetate. A reaction mechanism through metal-carbene and azomethine ylide is proposed.