2,3-dicyano-5,6-dichloro-p-benzoquinone in benzene 3 h; Heating;

1: 62 percent / N-bromosuccinimide / dimethylformamide / 12 h / 70 - 80 °C 2: 1) n-BuLi / 2) CoCl2 / 1) ether, hexane, -10 to 0 deg C, 2 h, 2) reflux, 12 h 3: 60 percent / 2,3-dichloro-5,6-dicyanoquinone (DDQ) / benzene / 3 h / Heating View Scheme

1: 1) n-BuLi / 2) CoCl2 / 1) ether, hexane, 0 deg C, 2 h, 2) reflux, 12 h 2: 62 percent / N-bromosuccinimide / dimethylformamide / 12 h / 70 - 80 °C 3: 1) n-BuLi / 2) CoCl2 / 1) ether, hexane, -10 to 0 deg C, 2 h, 2) reflux, 12 h 4: 60 percent / 2,3-dichloro-5,6-dicyanoquinone (DDQ) / benzene / 3 h / Heating View Scheme

1: 1) n-BuLi / 2) Ni(acac)2 / 1) ether, -10 to -30 deg C, 30 min, 2) a) -78 deg C, 1 h, b) room temp., 1 h, c) reflux, 1 h 2: 60 percent / 2,3-dichloro-5,6-dicyanoquinone (DDQ) / benzene / 3 h / Heating View Scheme

1: 1) n-BuLi / 2) CoCl2 / 1) ether, hexane, -10 to 0 deg C, 2 h, 2) reflux, 12 h 2: 60 percent / 2,3-dichloro-5,6-dicyanoquinone (DDQ) / benzene / 3 h / Heating View Scheme

1: 5 percent / benzene / 48 h / Irradiation 2: 60 percent / 2,3-dichloro-5,6-dicyanoquinone (DDQ) / benzene / 3 h / Heating View Scheme

1: 47 percent / Pb(OAc)4, BF3*Et2O / acetonitrile / 3 h / Ambient temperature 2: 1) Li 2) O2 / 1) THF, 4 h, reflux 2) 10 min 3: 29 percent / DDQ / benzene / 24 h / 80 °C View Scheme