Looking at the original text the acetylacetonate is produce via reaction with KOH/NaOH, and then dedydrated to get the Potassium/Sodium Acetylacetonate.
Bandil, you do think that preparing the electrophile via this method could produce different results?
I'm not sure why sodium carbonate was used, but is it strong enough to deprotonate the acetylacetone to the acetonate? I know that alpha carbon should deprotonate easily since its stablized by those oxygens. But maybe something stronger needs to be there.
edit: recalling o-chem classes, generally the claisen condensations used bases like NaOEt et. al. I'm sure the carbonate wasn't strong enough. Hopefully preparing the potassium/sodium acetylacetonate and then adding it to the solution may give better yields, I see no reason to why the that methylenedioxy bridge would deactivate the so severely.
If it is indeed the bridge, maybe starting with 5-bromo-1,3-benzenediol would provide better result, and then one could close the bridge with a methylenation reaction using dcm and a ptc?
edit 2: Looking over psychokitty's notes on synthesis of mdma precursors from eugenol, the paper talks about methylenation of the 3,4-dihydroxy(methyl)amphetamine to the desired product in 70-78% yields depending on whether the amine is protected or not.
Swim has been looking over this preceedure for quiet some time now, as it was his next project. Good luck Bandil! Swim is convinced this method can work!