“…In a 50 mL two-neck round-bottom flask equipped with a magnetic stirring bar, a rubber septum, and an argon balloon were placed nitrone S3a (686 mg, 3.48 mmol), CuI (66.3 mg, 0.348 mmol), 1,2-bis(diphenylphosphino)ethane (DPPE, 139 mg, 0.348 mmol), and K 2 CO 3 (529 mg, 3.83 mmol), and to it were added H 2 O (0.13 mL, 6.96 mmol) and 1-bromo-2-ethynylbenzene S2a (629 mg, 3.48 mmol) in DMF (14 mL) at room temperature. The mixture was stirred at 80 °C for 4 h. H 2 O (25 mL) was added to quench the reaction.…”