Iridium-Catalyzed Enantioselective Hydroamination of Allenes: Direct Access to Chiral α-Tertiary Allylic Amines

We described the first Ir(I)-catalyzed enantioselective hydroamination of allenes, providing a broadly applicable access to α-tertiary chiral allylamines, scaffolds that are largely inaccessible through other asymmetric strategies. The method displays a broad substrate scope, accommodating both aryland alkyl-substituted allenes. Removal of the pyridine group enables access to primary allylic amines bearing α-tetrasubstituted stereocenters, whereas the use of trisubstrituted allenes allows to obtain αsecondary allylic amines. Notably, addition of i-PrOH to the reaction media enables an in situ hydrogenation of the alkenyl moiety to deliver α-tertiary chiral amines. Computational studies support a hydrometalation/C-N bond-forming sequence as the preferred pathway, with the reductive elimination step being enantiodetermining. The computational analysis further rationalized the absolute configuration of the major enantiomer and the critical role of the counterion.