N,N,N',N,-tetramethylethylenediamine; sec.-butyllithium 1.) cyclohexane, THF, -78 deg C, 1 h, 2.) a) -78 deg C, 4 h, b) from -78 deg C to RT, 2 h, c) RT, 0.5 h; Yield given. Multistep reaction. Yields of byproduct given;