Synthesis of iminoaziridines from carbodiimides and diazoesters : A new example of transition metal salt catalysed reactions of carbenes

Alkyl diazoacetates react with N,N′-diisopropylcarbodiimide in the presence of transition metal salts (e.g. copper triflate or rhodium (II) acetate) to give 1-isopropyl-2-alkoxycarbonyl-3- isopropyliminio-aziridine in good yield. The reaction takes place at room temperature without formation of the formal dimer of the carbene (maleate and fumarate). © 1976.