Synthesis of N-alkoxy amines and hydroxylamines via the iridium-catalyzed transfer hydrogenation of oximes

Cationic iridium (Ir) complexes were found to catalyze the transfer hydrogenation of oximes to access N-alkoxy amines and hydroxylamines, and the reaction was accelerated by trifluoroacetic acid. The practical application of this protocol was demonstrated by a gram-scale transformation and two-step synthesis of the fungicide furmecyclox (BAS 389F) in overall yields of 92 and 85%, respectively. An asymmetric protocol using chiral Ir complexes to afford chiral N-alkoxy amines was demonstrated, but the low yields/ee obtained indicated that further development was required.

Automated summary

Cationic iridium complexes were demonstrated to catalyze the transfer hydrogenation of oximes, providing access to N-alkoxy amines and hydroxylamines. The reaction rate was accelerated by trifluoroacetic acid. The practical application of this method was demonstrated by the synthesis of a fungicide in high yields, and the asymmetric synthesis of chiral N-alkoxy amines showed potential for further development.