Fig. 3: Scope of alkynes in phosphonoiodination.

Reaction conditions: 1a (0.20 mmol, 1.0 equiv), 2 (0.40 mmol, 2.0 equiv), Tf₂O (0.21 mmol, 1.05 equiv), 2,6-di-tert-butylpyridine (0.40 mmol, 2.0 equiv), CHCl₃ (1.0 mL), 60 °C, 3 h, then I₂ (0.40 mmol, 2.0 equiv) was added for 18 h. Isolated yield.