benzeneseleninic anhydride in chlorobenzene T=120°C; 1.7 h;

1: 1.) sodium hydride / 1.) DMSO, -5 deg C, 35 min, 2.) DMSO, THF, a) -5 deg C, 2 h, b) RT, 20 h 2: 1) diisopropylethylamine, n-BuLi / 1.) THF, hexane, -15 deg C, 1 h, 2.) THF, hexane, RT, 20 h 3: 95 percent / 6M aq. KOH / methanol / 4 h / Heating 4: 76 percent / N-chlorosuccinimide, silver nitrate / H2O; acetonitrile / 0.5 h / Ambient temperature 5: 70 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / toluene / 5 h / 100 °C View Scheme

1: 1) diisopropylethylamine, n-BuLi / 1.) THF, hexane, -15 deg C, 1 h, 2.) THF, hexane, RT, 20 h 2: 95 percent / 6M aq. KOH / methanol / 4 h / Heating 3: 76 percent / N-chlorosuccinimide, silver nitrate / H2O; acetonitrile / 0.5 h / Ambient temperature 4: 70 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / toluene / 5 h / 100 °C View Scheme

1: 95 percent / 6M aq. KOH / methanol / 4 h / Heating 2: 76 percent / N-chlorosuccinimide, silver nitrate / H2O; acetonitrile / 0.5 h / Ambient temperature 3: 70 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / toluene / 5 h / 100 °C View Scheme

1: 76 percent / N-chlorosuccinimide, silver nitrate / H2O; acetonitrile / 0.5 h / Ambient temperature 2: 70 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / toluene / 5 h / 100 °C View Scheme

1: 21 percent / Jones' reagent / acetone / 0.67 h / 0 °C 2: 70 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / toluene / 5 h / 100 °C View Scheme

1: (n-Pr4N)(RuO4), 4-methylmorpholine N-oxide, molecular sieves / CH2Cl2 / Ambient temperature 2: 1.) t-BuLi / 1.) diethyl ether, pentane, -78 deg C, 1 h, 2.) diethyl ether, pentane, THF, -78 deg C, 11 h 3: 21 percent / Jones' reagent / acetone / 0.67 h / 0 °C 4: 70 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / toluene / 5 h / 100 °C View Scheme

1: 1.) t-BuLi / 1.) diethyl ether, pentane, -78 deg C, 1 h, 2.) diethyl ether, pentane, THF, -78 deg C, 11 h 2: 21 percent / Jones' reagent / acetone / 0.67 h / 0 °C 3: 70 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / toluene / 5 h / 100 °C View Scheme