Aziridine synthesis in protic media by using lanthanide triflates as catalysts

Abstract

Ln(OTf) 3-catalyzed aziridine synthesis from imines and diazo compounds was studied in a variety of protic media. The reactions proceeded readily under mild conditions and were highly selective, affording predominantly cis aziridines. The imines used were typically those derived from aromatic aldehydes and aromatic amines, with either electron-donating or electron-withdrawing substituents. N-benzyl aryl aldimines and imines derived from aromatic amines and hindered aliphatic aldehydes were also found to work well. Among the three diazo compounds examined, ethyl diazoacetate (EDA) and 3-nitrophenyl diazomethane were effective reagents for the aziridination. However, the reactions of ethyl diazoacetoacetate failed to give any desired product. Six lanthanides triflates as well as Sc(OTf) 3 and Y(OTf) 3 were tested as catalyst in the aziridination reaction. The formation of the by-products was also discussed.