Superparamagnetic Nanoparticle‐Supported (S)‐Diphenyl‐ prolinol Trimethylsilyl Ether as a Recyclable Catalyst for Asymmetric Michael Addition in Water

A new superparamagnetic nanoparticle‐supported (S)‐diphenylprolinol trimethylsilyl ether (Jørgensen–Hayashi catalyst) was synthesized and applied for the asymmetric Michael addition of aldehydes to nitroalkenes in water, which gives products in moderate to good yields (up to 96%), good enantioselectivity (up to 90% ee) and diastereoselectivities (up to 99:1). The immobilized catalyst could be easily separated from the reaction by an external magnet and recycled for four times without significant loss of catalytic efficiency.