n-butyllithium; N,N,N',N,-tetramethylethylenediamine in tetrahydrofuran 1.) 0 deg C, 1 h; 2.) -78 deg C, 1.5 h; -60 deg C, 1 h; -50 deg C, 2 h; -35 deg C, 0.5 h;

1: 1.) sodium hexamethyldisilazide, 2.) HMPA / 1.) THF, - 78 deg C, 1 h, 2.) THF, - 65 deg C, 16 h 2: n-butyllithium, TMEDA / 1.) THF, hexane, 0 deg C, 1 h, 2.) THF, hexane, - 78 deg C, 1.5 h, - 60 deg C, 1 h, - 50 deg C, 2 h, - 35 deg C, 0.5 h View Scheme

n-butyllithium; N,N,N',N,-tetramethylethylenediamine 1.) THF, hexane, 0 deg C, 1 h, 2.) THF, hexane, - 78 deg C, 1.5 h, - 60 deg C, 1 h, - 50 deg C, 2 h, - 35 deg C, 0.5 h; Yield given. Multistep reaction. Yields of byproduct given;