1: 1-methyl-2,3-dimethoxybenzene With N,N,N',N,-tetramethylethylenediamine; tert.-butyl lithium in diethyl ether; pentane T=20°C; 13 h; 2: N,N-dimethyl-formamide in diethyl ether; pentane T=20°C; 0.5 h; Further stages.;

n-butyllithium; N,N,N',N,-tetramethylethylenediamine in hexane 1.) 0 deg C, 30 min; r.t., overnight, 2.) 0 deg C, 1 h;

1.1: TMEDA; n-BuLi / tetrahydrofuran; hexane / 3.5 h / 20 °C 1.2: 84 percent / tetrahydrofuran; hexane / -78 - 20 °C 2.1: TMEDA; t-BuLi / diethyl ether; pentane / 13 h / 20 °C 2.2: 75 percent / diethyl ether; pentane / 0.5 h / 20 °C View Scheme

Yield given. Multistep reaction;