A 4 mL vial equipped with a stirring bar was charged with copper iodide (2.0 mg, 10 mol %), and Pd(PPh3)2Cl2 (3.5 mg, 5 mol %). A solution of 6-chloro-5-iodo-2-methanesulfonyl-1-(2-trimethylsilanyl-ethoxymethyl)-1H-benzoimidazole (Intermediate 5, 49.0 mg, 0.100 mmol) in DMF (0.5 mL) was added to the vial, followed by a solution of ethynyl-benzene (20.0 mg, 0.200 mmol) in DMF (0.5 mL) and TEA (98 uL, 0.70 mmol). The resulting suspension was stirred at rt for 10 min, during which time it gradually turned brown. The solvent was then removed in vacuo to give brown oily solid, which was suspended in 1:1 EtOAc/MeOH (3 mL) and passed through a Thiol StratoSphere™ SPE cartridge (Polymer Labs). The resulting solution was evaporated to dryness in vacuo to give light yellow oil. LR-MS (API-ES): calculated C22H25ClN2O3SSi 460.1, m/e (M+H)+ not observed, 433.0, 403 (Rt 3.83 min).
