Dendrimers or Nanoparticles as Supports for the Design of Efficient and Recoverable Organocatalysts?

The JOrgensen-Hayashi catalyst [(S)-,-diphenylprolinol trimethylsilyl ether] was grafted onto the surface of two different supports: phosphorus dendrimers (generations 1 to 3) and magnetic, polymer-coated cobalt/carbon (Co/C) nanobeads. These new supported catalysts displayed high activities and selectivities in the Michael additions of a wide range of aldehydes to different nitroolefins. Moreover, the dendrimer of the third generation displayed excellent recycling abilities since it could be recovered and reused in 7 consecutive runs without loss of activity.