1: 84 percent / p-toluenesulfonic acid / toluene / 10 h / Heating 2: 1.) n-butyllithium / 1.) ether, -10 deg C, 20 min, 2.) -5 deg C, 45 min View Scheme

1: 84 percent / p-toluenesulfonic acid / toluene / 10 h / Heating 2: 1.) n-butyllithium / 1.) ether, -10 deg C, 20 min, 2.) -5 deg C, 45 min View Scheme

n-butyllithium 1.) ether, -10 deg C, 20 min, 2.) -5 deg C, 45 min; Yield given. Multistep reaction;