1134-35-6

In a dry, N2-washed 50 mL round-bottom flask equipped with a magnetic stir bar, freshly prepared Grignard reagent (3 mmol) was added to anhydrous THF (3 mL) at the specified temperature. A solution of CuLi₂Cl₄ in anhydrous THF (5 mL, 0.15 mmol, 0.03 M) was added in a single injection using a syringe. Simultaneously, dry O₂ was bubbled into the mixture through a sleeve. After stirring for 2 hours, the flow of O₂ was stopped, and the mixture was quenched with a saturated aqueous solution of NH₄Cl (5 mL). The solvent was removed, and the aqueous layer was extracted with EtOAc (3 × 20 mL). The combined organic phases were washed with brine (20 mL), dried over anhydrous Na₂SO₄, and concentrated under vacuum. The residue was purified by rapid chromatography on silica gel to provide the product: 4,4'-Dimethyl-2,2'-bipyridyl (13b).

Figure 4,4'-Dimethyl-2,2'-bipyridyl