pyridine-SO3 complex; dimethyl sulfoxide; triethylamine T=0 - 20°C; 20 h;

1: 84 percent / CrO3 / acetone / 3 h 2: 90 percent / NH3 / H2O / Heating View Scheme

1: 2-fluoro-pyridine With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-78 - 0°C; 5 h; 2: acetaldehyde in tetrahydrofuran; hexane T=-78 - 20°C; 21 h; 3: With water in tetrahydrofuran; hexane