1: With n-butyllithium in tetrahydrofuran; pentane T=-78°C; 1 h; 2: With water; ammonium chloride in tetrahydrofuran; pentane

1.1: 2-Bromo-1,3,5-trimethyl-benzene; tert.-butyl lithium / tetrahydrofuran; pentane / 3 h / -23 °C 1.2: 1 h / -78 °C 1.3: -78 - 20 °C 2.1: triphenylphosphine / dichloromethane / 1 h / 0 °C 3.1: n-butyllithium / tetrahydrofuran; pentane / 1 h / -78 °C View Scheme

1: triphenylphosphine / dichloromethane / 1 h / 0 °C 2: n-butyllithium / tetrahydrofuran; pentane / 1 h / -78 °C View Scheme