toluene-4-sulfonic acid in methanol 24 h; Ambient temperature;

1: 1.) lithium amide / 1.) liq. ammonia, 2 h, 2.) THF, -33 deg C, 6 h 2: 65 percent / triphenylphosphine, carbon tetrachloride / 6 h / Heating 3: 1.) CuI / 1.) ether, room temperature, 1 h, 2.) THF, 4 h, room temperature 4: 85 percent / PTS acid / methanol / 24 h / Ambient temperature View Scheme

1: 1.) lithium amide / 1.) liq. ammonia, 2 h, 2.) THF, -33 deg C, 6 h 2: 65 percent / triphenylphosphine, carbon tetrachloride / 6 h / Heating 3: 1.) CuI / 1.) ether, room temperature, 1 h, 2.) THF, 4 h, room temperature 4: 85 percent / PTS acid / methanol / 24 h / Ambient temperature View Scheme

1: 65 percent / triphenylphosphine, carbon tetrachloride / 6 h / Heating 2: 1.) CuI / 1.) ether, room temperature, 1 h, 2.) THF, 4 h, room temperature 3: 85 percent / PTS acid / methanol / 24 h / Ambient temperature View Scheme

1: 1.) CuI / 1.) ether, room temperature, 1 h, 2.) THF, 4 h, room temperature 2: 85 percent / PTS acid / methanol / 24 h / Ambient temperature View Scheme

1: 97 percent / Amberlyst H 15 / hexane / 0.67 h / 0 °C 2: 1.) (i-Pr)2NH, 1.8 M BuLi/n-hexane / 1.) THF, 3 h, room temp., 2.) THF, 12 h, 55 deg C 3: Amberlyst H 15 / methanol / 1 h / 45 °C 4: KHSO4 / Heating View Scheme

potassium hydrogensulfate Heating; Yield given. Yields of byproduct given. Title compound not separated from byproducts;