hydrogen; ammonium formate; palladium on activated charcoal in ethanol T=50°C; 6 h;

1: 3-fluoro-4-chloro pyridine With n-butyllithium in tetrahydrofuran; hexane T=-75°C; 20 h; 2: carbon dioxide in tetrahydrofuran; hexane

1.1: LDA / tetrahydrofuran; hexane / 2 h / -75 °C 1.2: 57 percent / 1,1,2-trichloro-2,2,1-trifluoroethane / tetrahydrofuran; hexane 2.1: BuLi / tetrahydrofuran; hexane / 20 h / -75 °C 2.2: 87 percent / tetrahydrofuran; hexane View Scheme