Enantioselective organic reaction not working I'm performing the reaction between acetone and 2-nitrobenzaldehyde catalysed by (L)-Proline, as answered to one of my questions a while ago: Simple experiments involving enantiomer synthesis

However, while the literature specified using 1 mmol of (L)-Proline in 20ml of solution, due to the cost of the materials and the budget available, I've only been able to use a fraction of that, around 0.01mmol. I've scaled down the entire experiment to 5 ml to try and compensate for this.

The issue is, I've left this solution reacting for a long period of time (12+ hours) and I'm not seeing any optical activity at all. With the reduced concentrations, I'd have expected to see a lot less activity than the original literature specifies, but to see at least some indication that my reaction is working.

Are the concentrations of (L)-Proline simply too small for any significant reaction to take place? Or can there be some other reason why my reaction isn't working? Note: I'm a chemistry 'newbie', so don't assume anything!
The original "Rutgers' reference" deploys $2\,\mbox{mmol}$ aldehyde in $20\,\mbox{mL}$ solvent (i.e. starting at $0.1\,\mbox{mol/L}$, or $0.1\,\mbox{M}$) and recommends a stirring of $3\,\mbox{h}$.


Subsequently, you mention $1\,\mbox{mmol}$ per $20\,\mbox{mL}$ solvent (i.e. starting at $0.05\,\mbox{M}$), but without an indication of reaction time.


But if the starting concentration is lowered further ($0.01\,\mbox{mmol}$ in $5\,\mbox{mL}$ equals to $0.002\,\mbox{M}$ or $2\,\mbox{mM}$), not only the detection of the product becomes difficult. Did you take into consideration that by diluting the reaction you over-proportionally slowed down the advancement of the intended reaction?  Compared to the initially mentioned starting concentration, your reaction starts at a dilution by a factor of 50 (fifty).  This is more than a big factor for process involving a bimolecular reaction.


By the way, $0.01\,\mbox{mmol}$ of proline, molar weight of $115.13\,\mbox{g/mol}$ as stated here would correspond to little more than $1.1\,\mbox{mg}$.