4-Pentynoic acid ethyl ester → Ethyl 5-(pyridin-2-yl)pent-4-ynoate

Participants

Reaction Steps

In a dry reaction tube containing in suspension copper iodide (60 mg, 0.315 mmol) and triethylamine (17.70 mL, 126 mmol), were added 2-iodopyridine (1.29 g, 6.30 mmol), and the Pd(PPh3)2Cl2 (202 mg, 0.315 mmol). A yellow suspension is obtained and after a few minutes of stirring at room temperature, was added ethyl pent-4-ynoate (790 mg, 6.30 mmol) in solution in 2 mL of triethylamine. Immediately the color of the reaction turns to black. The mixture was stirred at room temperature for 30 min and then at 80° C. for 20 h. Triethylamine was concentrated under reduce pressure and the residue was dissolved in DCM. The organic layer was washed with saturated NH4Cl, water and brine. The solvent was removed under reduced pressure and the crude product was purified by flash chromatography system (prepacked silicagel column 25 g, DCM/MeOH: 98/2 as eluent) to afford 1.17 g of ethyl 5-(pyridin-2-yl)pent-4-ynoate (Yield: 78%) as brownish oil.

Provenance & Evidence