[Piciszunyog]

I study heterogeneous Michael-addition between isobutyraldehyde and N-phenylmaleimide. I immobilized chiral 1,2-diphenylethylenediamine catalyst on polystryrene resin and silicagel supports too.
The first catalyst gave high enantioselectivity and conversion as well. On the other hands when I used the silicagel supported catalyst I achieved much lower values.
I wonder what is the difference between the organic and inorganic supports?
Can the acidic hydroxyl groups of the silica take parts of the reaction?
Any help here would be appreciated.

[wildfyr]

Silica gel is pretty acidic, and michael addition is definitely acid/base sensitive. What if you made a polystyrene resin that had some acidic groups on it too, that could be your "control" to see whether its the acid or the organic-ness that is that source of enantioselectivity or conversion. Were both lower with silica gel?