Efficient asymmetric transfer hydrogenation of N-sulfonylimines on water

An efficient and green approach for synthesis of optically active amines was developed via asymmetric transfer hydrogenation of N-sulfonyl ketimines catalyzed by the chiral and lipophilic rhodium-amido complex on water. Higher reactivity and enantioselectivity were observed on the hydrogenation of the solid substrate in an aqueous suspension compared to organic homogeneous phases. In the heterogeneous aqueous reaction, the reactivity depends on stirring speed and the recrystallized conditions of the solid substrate.