2,3-dicyano-5,6-dichloro-p-benzoquinone in dichloromethane Ambient temperature;

Multi-step reaction with 2 steps 1.1: n-BuLi / tetrahydrofuran / 0.33 h / -60 °C1.2: t-BuLi / tetrahydrofuran / 2.5 h / -75 - -40 °C1.3: I2 / tetrahydrofuran / -75 - 20 °C2.1: 32 percent / acetic anhydride / 5 h / Heating  

With  2,3-dicyano-5,6-dichloro-p-benzoquinone; toluene-4-sulfonic acid in  chlorobenzene  Heating;