silica gel in dimethyl sulfoxide

1: With pyridine; benzeneselenenyl chloride in dichloromethane 0.25 h; cooling; 2: With dihydrogen peroxide 0.25 h; Further stages.;

1.1: t-BuOK / tetrahydrofuran / 1 h / 20 °C 1.2: 83 percent / H2SO4 / H2O / 16 h / 20 °C 2.1: phenylselenyl chloride; pyridine / CH2Cl2 / 0.25 h / cooling 2.2: 50 percent / aq. H2O2 / 0.25 h View Scheme