The catalytic transfer hydrogenation of imines and the reductive amination of carbonyl compounds have been thoroughly investigated with a cyclooctene‐derived (cyclopentadienone)iron pre‐catalyst. Additionally, enantioselective ketimine reduction with a chiral (cyclopentadienone)ironcomplex is reported here for the first time.
An oxidative kinetic resolution of racemic acyclic amines was developed using an imine derivative as the resolving reagent and chiral phosphoric acid as the catalyst to give enantiomers in good yields with high to excellent enantioselectivities. The key to success of the title reaction was the equilibrium control by adjusting the ratio of the resolving reagent, and unique enantiodivergence was observed
Control with an iron hand: A broad range of ketimines underwent enantioselectivehydrogenation in the presence of a chiralBrønsted catalyst and a well‐defined nonchiral iron catalyst (see scheme). This procedure constitutes an attractive and environmentally favorable alternative to well‐established asymmetric hydrogenation reactions with precious‐metal catalysts.
AbstractThe direct asymmetric reductive amination (DARA) of ketones with anilines is described by combining a chiral Brønsted acid (TRIP) and the non‐chiral Knölker iron complex as the catalyst system. In situ‐formed imines are reduced with molecular hydrogen to give chiral amines in high yields (90%) and enantioselectivities of up to 99% ee.magnified image