potassium carbonate in N,N-dimethyl-formamide 48 h; Ambient temperature;

1: 1) p-toluenesulfonic acid / 1) benzene, 19 h, reflux, 2) diphenyl ether, 30 min, reflux 2: 9.5 percent / potassium carbonate / dimethylformamide / 48 h / Ambient temperature View Scheme

1: sodium ethoxide / ethanol / 5 h / Ambient temperature 2: 1) p-toluenesulfonic acid / 1) benzene, 19 h, reflux, 2) diphenyl ether, 30 min, reflux 3: 9.5 percent / potassium carbonate / dimethylformamide / 48 h / Ambient temperature View Scheme

1: 1) sodium hydride / 1) ether, 3h, room temperature, 2) 16 h 2: sodium ethoxide / ethanol / 5 h / Ambient temperature 3: 1) p-toluenesulfonic acid / 1) benzene, 19 h, reflux, 2) diphenyl ether, 30 min, reflux 4: 9.5 percent / potassium carbonate / dimethylformamide / 48 h / Ambient temperature View Scheme

1: 1) p-toluenesulfonic acid / 1) benzene, 19 h, reflux, 2) diphenyl ether, 30 min, reflux 2: 9.5 percent / potassium carbonate / dimethylformamide / 48 h / Ambient temperature View Scheme

n-butyllithium; diisopropylamine 1) THF, hexane, -78 deg C, 1 h, 2) -78 deg C, 15 min; Yield given. Multistep reaction;