A solution of 2-iodo adenosine (200 mg, 0.51 mmol), 3,4,5-trifluorophenylboronic acid (107 mg, 0.609 mmol), cesium carbonate (364 mg, 1.12 mmol) and Pd(PPh3)4 (59 mg, 0.051 mmol) in toluene (1.2 mL) and ethanol (2.4 mL) was heated in a Biotage microwave (120° C., absorption high, pre-stirring 30 s) for 40 min. The solvents were then removed in vacuo and the residue dissolved in EtOAc (30 mL) and washed with sat. aq. NaHCO3 (20 mL×2) and brine (20 mL) and dried over MgSO4. Purification by flash column chromatography (normal phase, ICN silica, 50 g, 18-32%, gradient 2.5-15% ethanol in DCM, residue dry loaded, product eluted in 15% ethanol) and by reverse phase prep HPLC (Phenomenex Synergi, RP-Hydro 150×10 mm, 10μ, 20 mL per min, gradient 5-100% acetonitrile in water over 10 min, product eluted in 50% acetonitrile) afforded (2R,3R,4S,5R)-2-{6-amino-2-(3,4,5-trifluorophenyl)-9H-purin-9-yl}-5-(hydroxymethyl) tetrahydrofuran-3,4-diol 12 as a white solid (13.2 mg, 7%).
