1: With 2-hydroxy-1,3-isoindolinedione; azobisisobutyronitrile; oxygen in acetonitrile T=75°C; P=760.051 Torr; 21 h; 2: With sulfuric acid in acetonitrile T=25°C; 2 h; Further stages.;

boron tribromide in dichloromethane T=-78°C; 0.5 h;

1: 73 percent / NiCl2(dppe) / diethyl ether / 22 h / 40 °C 2: 81 percent / BBr3 / CH2Cl2 / 0.5 h / -78 °C View Scheme

1: 43 percent / K2CO3 / dimethylformamide / 12 h / 45 °C 2: 98 percent / pyridine / 0.5 h 3: 73 percent / NiCl2(dppe) / diethyl ether / 22 h / 40 °C 4: 81 percent / BBr3 / CH2Cl2 / 0.5 h / -78 °C View Scheme

1: 98 percent / pyridine / 0.5 h 2: 73 percent / NiCl2(dppe) / diethyl ether / 22 h / 40 °C 3: 81 percent / BBr3 / CH2Cl2 / 0.5 h / -78 °C View Scheme