1: 89 percent / O2 / Co(Salpr) / CH2Cl2 / 1 h / 0 °C 2: 95 percent / KOH / aq. ethanol / 0.5 h / 0 °C / various solvents: DMF, THF, t-BuOH, other temperature: 25 deg C and catalyst: t-BuOK View Scheme

1: 89 percent / O2 / Co(Salpr) / CH2Cl2 / 1 h / 0 °C 2: 25 percent / t-BuOK / dimethylformamide / 0.5 h / 25 °C / various solvents: THF, t-BuOH, 90percent aq-EtOH, catalyst: KOH and temperature: 0 deg C View Scheme

1: 89 percent / O2 / Co(Salpr) / CH2Cl2 / 1 h / 0 °C 2: 40 percent / t-BuOK / dimethylformamide / 0.5 h / 25 °C / various solvents: THF, t-BuOH, 90percent aq-EtOH, catalyst: KOH and temperature: 0 deg C View Scheme

1: 89 percent / O2 / Co(Salpr) / CH2Cl2 / 1 h / 0 °C 2: 76 percent / Me2S / 0 °C View Scheme