in N,N,N',N',N'',N''-hexamethylphosphoric triamide; N,N-dimethyl-formamide T=60°C; 1.5 h;

1: 91 percent / p-TsOH*H2O / diethyl ether / 18 h / Heating 2: 1) BuLi, 2) iodine / 1) THF, -78 deg C, 30 min, 2) a) THF, -78 deg C, 10 min, b) to room temperature 3: 47 percent / dimethylformamide; hexamethylphosphoric acid triamide / 1.5 h / 60 °C View Scheme

1: 1) BuLi, 2) iodine / 1) THF, -78 deg C, 30 min, 2) a) THF, -78 deg C, 10 min, b) to room temperature 2: 47 percent / dimethylformamide; hexamethylphosphoric acid triamide / 1.5 h / 60 °C View Scheme

n-butyllithium 1) ether, -78 deg C, 30 min; 2) 25 deg C, 3 h; Yield given. Multistep reaction. Yields of byproduct given;