1: thiophen-2-yl-acetic acid 2: N,N-dimethylformamide-dimethylsulfonate complex With lithium diisopropyl amide in tetrahydrofuran; n-heptane T=0°C; 1.5 h; 3: in tetrahydrofuran T=-70 - 20°C; 1 h;

lithium diisopropyl amide 1.) THF, hexane, room temp., 1 h; 2.) THF, 25 deg C, 60 min; Yield given. Multistep reaction;