Oxidative Kinetic Resolution of Acyclic Amines Based on Equilibrium Control.

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 depending on the equilibrium displacement.

Chiral phosphoric acid catalyzed oxidative kinetic resolution of cyclic secondary amine derivatives including tetrahydroquinolines by hydrogen transfer to imines.

A chiral Brønsted acid catalyzed dehydrogenative kinetic resolution of tetrahydroquinoline derivatives, which are representative of cyclic secondary amines, based on their hydrogen transfer to aromatic imines was efficiently achieved with high enantioselectivities. This hydrogen transfer of tetrahydroquinolines to imines was not driven by their aromatization to quinolines. This dehydrogenative kinetic resolution could be also applied to the asymmetric synthesis of various benzofused heterocycles containing secondary amine cores.

Asymmetric transfer hydrogenation of ketimines by indoline as recyclable hydrogen donor.

The chiral phosphoric acid catalyzed enantioselective transfer hydrogenation of various ketimines was achieved by the use of 2-aryl indoline as the hydrogen donor. Corresponding chiral amines were obtained in good chemical yields with excellent enantioselectivities.