1: 1.) n-BuLi / 1.) THF, hexane, -78 deg C, 3 h 2: silica gel / hexane View Scheme

n-butyllithium 1) THF, hexane, -95 to -100 deg C, 30 min; 2) THF, -95 deg C, 2 - 3 h; Multistep reaction. Yields of byproduct given;