5,6-Dichloro-2-iodo-3-pyridinol (632 mg, 2.2 mmol), copper(I) iodide (75 mg, 0.40 mmol), bis(triphenylphosphine)palladium(II) chloride (77 mg, 0.11 mmol) and triethylamine (370 mL, 2.6 mmol) were combined in DMF (2.7 mL) and allowed to stir for 1 hour. 1-t-Butyloxycarbonyl-2-(R)-ethynylpyrrolidine (510 mg, 2.6 mmol) in DMF (1 mL) was added and the mixture was heated to 60° C. for 16 hours. After cooling to ambient temperature, the mixture was poured over Et2O/saturated K2CO3 solution and the phases were separated. The organic phase was washed with brine:water (1:1) (4×), dried (MgSO4) and concentrated. The residue was chromatographed (silica gel; EtOAc/hexane, 1:6) to afford an amber oil (365 mg, 46%): 1H NMR (CDCl3, 300 MHz) δ 1.32 and 1.45 (two br s, 9H), 1.95-2.40 (m, 4H), 3.45-3.74 (m, 2H), 4.92-5.13 (m, 1H), 6.62 (s, 1H), 7.81 (s, 1H); MS (CI/NH3) m/z: 357 (M+H)+.
