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With [2,2]bipyridinyl; (1,5-cyclooctadiene)(methoxy)iridium(I) dimer In 1,4-dioxane at 40℃; for 4 h; Inert atmosphere; Schlenk technique
General procedure: Ligand (0.010 mmol) and [Ir(OMe)(cod)]2 (3.3 mg, 0.0050 mmol) were placed in a 20-mL two-necked reaction flask, which was filled with N2 by using the standard Schlenk technique. Solvent (0.50 mL) was injected via a syringe, and the mixture was stirred for 5 min at r.t. A solution of 2-pyridone (0.25 mmol) and bis(pinacolato)diboron(0.38–0.75 mmol) in solvent (1.0 mL) was then added, and the suspension was stirred under the indicated conditions. The resulting mixture was allowed to cool to r.t., diluted with EtOAc, and filtered through a short pad of neutral alumina and anhyd Na2SO4. After concentration under reduced pressure, purification by GPC (EtOAc) afforded the corresponding borylated 2-pyridone.
General procedure: In a dry Schlenk tube 6-methyl-2(1H)-pyridone (1) (3.43 g, 31.44 mmol) was dissolved in 50 mLof 1,4-dioxane and KOt-Bu (8.69 g, 62.88 mmol) was added. The mixture was stirred at 100 C for 2 h, then cooled down to rt, MeI (19.6 mL, 314.41 mmol) was added dropwise and the mixture was stirred at 80 C for 16 h. The solvent was removed under reduced pressure and the residue was separated between DCM and water. The extraction was performed using DCM (3×) and the combined organic phases were dried over MgSO4, filtered and evaporated. The residue was transferred to a column chromatography (5% MeOH in DCM) to afford 3a (orange solid), 3.70 g (96%).
With potassium carbonate; In acetone; at 55℃; for 16h;sealable flask;
Iodomethane (10.62 mL, 1 11.6 mmol) was added to a mixture of 3-methyl-2-pyridone (4.06 g, 37.20 mmol) and potassium carbonate (15.43 g, 111.6 mmol) in acetone (150 mL) in a sealable flask. The mixture was vigorously stirred in an oil bath at 55 C for 16 hours. The reaction mixture was cooled to ambient temperature then filtered through glass fiber filter paper and the filtrate was concentrated under vacuum until a solid formed (5.4 g). The solid was partitioned between water (50 mL) and dichloromethane (100 mL). The aqueous phase was extracted once more with dichloromethane (50 mL). The combined organic phases were dried over magnesium sulfate and concentrated under vacuum to give l,3-dimethylpyridin-2(lH)-one as an oil (3.6 g).
With bis(1,5-cyclooctadiene)nickel (0); bis(2,6-di-tert-butyl-4-methylphenoxide)methylaluminum; 1,3-bis-(2,6-diisopropylphenyl)-imidazol-2-ylidene In toluene at 80℃; for 9h; Inert atmosphere; regioselective reaction;
With [2,2]bipyridinyl; (1,5-cyclooctadiene)(methoxy)iridium(I) dimer; In 1,4-dioxane; at 40℃; for 4.0h;Inert atmosphere; Schlenk technique;
General procedure: Ligand (0.010 mmol) and [Ir(OMe)(cod)]2 (3.3 mg, 0.0050 mmol) were placed in a 20-mL two-necked reaction flask, which was filled with N2 by using the standard Schlenk technique. Solvent (0.50 mL) was injected via a syringe, and the mixture was stirred for 5 min at r.t. A solution of 2-pyridone (0.25 mmol) and bis(pinacolato)diboron(0.38-0.75 mmol) in solvent (1.0 mL) was then added, and the suspension was stirred under the indicated conditions. The resulting mixture was allowed to cool to r.t., diluted with EtOAc, and filtered through a short pad of neutral alumina and anhyd Na2SO4. After concentration under reduced pressure, purification by GPC (EtOAc) afforded the corresponding borylated 2-pyridone.