tetrafluoroboric acid; sodium nitrite T=-60 - -40°C; 3 h; Irradiation;

1: 65.5 percent / formamidinesulfinic acid (FASA) / NEt3 / methanol; H2O / 20 h / 45 - 50 °C 2: 53 percent / 50percent HBF4 / aq.NaNO2 / 3 h / -60 - -40 °C / Irradiation View Scheme

1: 39.2 percent / 50percent HBF4 / NaNO2 / H2O / 4 h / -60 - -40 °C / Irradiation 2: 1) aq.NaNO2 / 1) 2N HCl (ice-cold) 2) 10percent Na2CO3 (ice-cold) 3: 65.5 percent / formamidinesulfinic acid (FASA) / NEt3 / methanol; H2O / 20 h / 45 - 50 °C 4: 53 percent / 50percent HBF4 / aq.NaNO2 / 3 h / -60 - -40 °C / Irradiation View Scheme

1: 1) aq.NaNO2 / 1) 2N HCl (ice-cold) 2) 10percent Na2CO3 (ice-cold) 2: 65.5 percent / formamidinesulfinic acid (FASA) / NEt3 / methanol; H2O / 20 h / 45 - 50 °C 3: 53 percent / 50percent HBF4 / aq.NaNO2 / 3 h / -60 - -40 °C / Irradiation View Scheme

sodium hydroxide 72 h; Ambient temperature;

1: 81 percent / NEt3 / CH2Cl2 / 2 h / Ambient temperature 2: NaBH4 / propan-1-ol / Ambient temperature View Scheme