Asymmetric Hydrogenation of Imines Using NHC‐Phosphine Iridium Complexes

Abstract α‐Chiral amines represent a frequently observed functional group in pharmaceuticals. Here, the synthesis of such motifs (up to 91% ee ) is described by asymmetric hydrogenation of imines catalyzed by NHC,P‐iridium complexes. The hydrogenation proceeded smoothly, even under balloon pressure of hydrogen atmosphere. Mechanistic experiments indicated that the reduction most likely advances by a combination of direct hydrogenation and a hydrogen transfer process using either H 2 or i PrOH as the reductant, respectively.