Under argon, to a solution of 2-iodoadenosine (200 mg, 0.51 mmol) and bis(triphenylphosphine)palladium dichloride (36 mg, 10 mol %) dissolved in N,N-dimethylformamide (5 mL), triethylamine (0.09 mL, 0.61 mmol, 1.2 eq.) and 7-cyano-1-heptyne (74 mg, 0.1 mmol, 1.2 eq.) were added, and, under ice-cooling conditions, cuprous iodide (10 mg, 5 mol %) was added thereto, followed by stirring at 60° C. for 24 hours. The reaction mixture was cooled to room temperature, and the solvent was removed under reduced pressure. The residue was purified by dry packed silica gel column chromatography (chloroform:methanol=10:1), to thereby yield the above-titled compound as a pale yellow powder (yield: 77 mg, percent yield: 39%).
