1: 1.) p-TsOH, 2.) 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) / 1.) benzene, reflux, 2h, 2.) reflux, 4h 2: 88 percent / aq. KOH / methanol / 1 h / Heating View Scheme

1: 1.) p-TsOH, 2.) 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) / 1.) benzene, reflux, 2h, 2.) reflux, 4h 2: 88 percent / aq. KOH / methanol / 1 h / Heating 3: 88 percent / anhydrous HF / 15 h / Ambient temperature View Scheme

1: 1.) p-TsOH, 2.) 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) / 1.) benzene, reflux, 2h, 2.) reflux, 4h 2: 88 percent / aq. KOH / methanol / 1 h / Heating 3: 88 percent / anhydrous HF / 15 h / Ambient temperature 4: 95 percent / Sodium borohydride / dimethylformamide / 6 h / Ambient temperature 5: 62 percent / p-TsOH / benzene / 0.75 h / Heating View Scheme