Step 1: 2,6-Dichloropyridine (11) (8.88 g, 60.0 mmol) and 2-(tributylmethylstannyl)pyridine (7.36 g, 20.0 mmol) were dissolved in anhydrous toluene (74 mL) under nitrogen protection. To this solution was added tetrakis(triphenylphosphine)palladium (2.31 g, 2.0 mmol), followed by heating the reaction mixture to reflux and stirring for 11 hours. Upon completion of the reaction, the mixture was concentrated under reduced pressure and the residue was purified by silica gel column chromatography to afford the target product 6-chloro-2,2'-bipyridine (12) (3.9 g, quantitative yield). The structure of the product was confirmed by 1H-NMR (DMSO-d6): δ 7.50-7.53 (m, 1H), 7.59 (d, 1H, J = 8.0 Hz), 7.93-8.05 (m, 2H), 8.30 (d, 1H, J = 8.0 Hz), 8.38 (d, 1H, J = 8.0 Hz), 8.72 (d, 1H, J = 4.4 Hz ).
