Chiral Cu(II)‐N 4 Complex Catalyzed Asymmetric Aza‐Henry Reaction and Its Application in the Synthesis of β ‐Diamine

Abstract Chiral Cu(II)‐L 3 complex was generated In situ to catalyze the asymmetric aza‐Henry reaction of various isatin derived N ‐Boc ketimines with nitromethane, nitroethane and 1‐nitropropane as nucleophiles at room temperature. High yield (up to 84 %) and excellent chiral induction (ee, up to 99 %) of β ‐nitroamine was obtained in 13 h. The β ‐nitroamine (1 g) was conveniently hydrogenated to enantiomerically pure ( S )‐ β ‐diamine in good yield and high enantioselectivity. The kinetic investigation was undertaken to understand the reaction mechanism of the catalytic aza‐Henry reaction using Cu(II)‐L 3 as catalyst, with nitromethane and isatin N ‐Boc ketimine (1 g) as a representative substrate.