1: 4-(4-fluorophenyl)-1-methylpiperidine-2,6-dione With (R,S,S,R)-PhCH(Me)N(Li)CH(Ph)CH(Ph)N(Li)CH(Me)Ph in tetrahydrofuran; hexane T=-78°C; 2: methoxycarbonyl cyanide in tetrahydrofuran; hexane T=-78 - -40°C; Title compound not separated from byproducts;