sodium chlorite; potassium dihydrogenphosphate; aminosulfonic acid in water; dimethyl sulfoxide T=20°C; 1 h;

1: 3,5-Difluorobenzonitrile With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.75 h; 2: carbon dioxide in tetrahydrofuran; hexane 0.416667 h; Cooling with ice;

1.1: lithium diisopropyl amide / tetrahydrofuran / 1 h / -78 °C 1.2: 0.75 h 2.1: aminosulfonic acid; potassium dihydrogenphosphate; sodium chlorite / water; dimethyl sulfoxide / 1 h / 20 °C View Scheme