Fig. 6: Synthesis of benzo[b]phosphole oxides by radical cyclization of 3.

Reaction conditions: 3 or 4 (0.10 mmol, 1.0 equiv), 8-hydroxyquinoline (0.02 mmol, 20 mol%), Cs2CO3 (0.2 mmol, 2.0 equiv), DMF (2.0 mL), 110 °C, 12 h. Isolated yield.

Reaction conditions: 3 or 4 (0.10 mmol, 1.0 equiv), 8-hydroxyquinoline (0.02 mmol, 20 mol%), Cs2CO3 (0.2 mmol, 2.0 equiv), DMF (2.0 mL), 110 °C, 12 h. Isolated yield.