Isomerization of Aziridines to Allyl Amines via Titanium and Chromium Cooperative Catalysis.

A Ti/Cr cooperative catalyst isomerizes aziridines to allyl amines under mild conditions. The reaction tolerates a broad range of aziridines with various nitrogen substituents. The titanium catalyst is most successful in opening 1,2-disubstituted aziridines, forming radical intermediates in a highly regioselective manner. The chromium catalyst appears to abstract an H • from these radical intermediates and then return the H • to the titanium system in the form of an H + and an electron. The reaction is complementary to previous reports on the isomerization of aziridines to allyl amines.