1: 4-ethynyl-N,N-dimethylbenzenamine With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 1 h; Inert atmosphere; 2: formic acid ethyl ester in tetrahydrofuran; hexane T=-78 - -30°C; 2 h; Inert atmosphere;

1: 4-ethynyl-N,N-dimethylbenzenamine With n-butyllithium in tetrahydrofuran; hexane T=-78°C; Metallation; 0.333333 h; 2: formic acid methyl ester in tetrahydrofuran; hexane T=-78 - 20°C; Addition; 0.333333 h;

1.1: 90 percent / CuI; PPh3; piperidine / bis(triphenylphosphine)palladium(II) chloride / 8 h / Heating 2.1: 82 percent / tetrabutylammonium fluoride / tetrahydrofuran; H2O / 1 h / 0 °C 3.1: n-BuLi / tetrahydrofuran; hexane / 0.33 h / -78 °C 3.2: 57 percent / tetrahydrofuran; hexane / 0.33 h / -78 - 20 °C View Scheme

1.1: 82 percent / tetrabutylammonium fluoride / tetrahydrofuran; H2O / 1 h / 0 °C 2.1: n-BuLi / tetrahydrofuran; hexane / 0.33 h / -78 °C 2.2: 57 percent / tetrahydrofuran; hexane / 0.33 h / -78 - 20 °C View Scheme