1: benzenesulfonic Acid With n-butyllithium in tetrahydrofuran; hexane T=0 - 25°C; 0.5 h; 2: chlorobis(2,6‐dimethoxyphenyl)phosphine in tetrahydrofuran; hexane T=0 - 25°C; 3 h;

1.1: N,N-diethylphosphoramidous dichloride / toluene / 2 h / 20 °C 2.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / 0 - 25 °C 2.2: 3 h / 0 - 25 °C View Scheme

1.1: n-butyllithium / hexane; pentane / 20 °C 2.1: N,N-diethylphosphoramidous dichloride / toluene / 2 h / 20 °C 3.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / 0 - 25 °C 3.2: 3 h / 0 - 25 °C View Scheme