1: 1.) hexamethyldisilazane, 1.6 M n-BuLi, 2.) CS2, 3.) PhSeO2H / 1.) THF, hexane, -20 deg C, 30 min, 2.) THF, rt, 3.) THF, rt, 5 h 2: oxalyl chloride, DMF / benzene / Ambient temperature View Scheme

carbon disulfide; n-butyllithium; benzeneseleninic acid; 1,1,1,3,3,3-hexamethyl-disilazane 1.) THF, hexane, -20 deg C, 30 min, 2.) THF, rt, 3.) THF, rt, 5 h; Yield given. Multistep reaction;

water in 1,4-dioxane 40 h; Ambient temperature;

1: 30 percent / 50percent aq. NaOH / n-Bu4NHSO4 / CH2Cl2; CHCl3 / 12 h 2: 58 percent / trifluoroacetic acid / CH2Cl2 / 0.25 h / -10 °C / Irradiation 3: 93 percent / water / dioxane / 40 h / Ambient temperature View Scheme

1: 58 percent / trifluoroacetic acid / CH2Cl2 / 0.25 h / -10 °C / Irradiation 2: 93 percent / water / dioxane / 40 h / Ambient temperature View Scheme

dicyclohexyl-carbodiimide in dichloromethane