if you reacted p-methoxyphenyl-2-bromopropane with tempidone hcl ala seigfried would you get 1-(paramethoxyphenyl-2-propyl) 2,2,6,6 tetrametoxy-4-piperidone in at least 10% yeild?
I'm sure that you would get a considerably higher yield reacting 1-(p-methoxyphenyl)-2-amino-propane (aka PMA) with phorone. The steric hinderance would not be so much of an obstacle as whith the N-alkylation reaction.