Fig. 3: Control experiments for mechanistic investigation.

For detailed conditions, see Supplementary Information including a control experiment to determine the key factors affecting the occurrence of reactions. [Ir-1], [Ir(dF(CF₃ppy)₂)(5,5′-CF₃-bpy)]PF_6. AcO^tBu, tert-butyl acetyl ester. TMG, N, N’-Tetramethylguanidine. n.d., not detected. a Control experiments for mechanistic study. b Fluorescence quenching studies of photocatalysts Ir-1 (the varied colors lines represent corresponding data at different quench concentrations). [Co], Co(dmgH)₂pyCl. [S], 1n. c To test if the 1a’ is the key intermediate in the reaction. Standard conditions: 1n (0.1 mmol), B₂pin₂ (1.5 eq), [Ir-1] (3 mol%), [Co-1] (15 mol%), TMG (50 mol%), tert-Butyl acetate (2 mL), 440 nm LED, 24 h. RT, room temperature. d Radical trapping or inhibiting experiments. Yield was determined by HPLC with 1,3,5-trimethoxybenzene as an internal standard. TEMPO, 2,2,6,6-Tetramethyl-1-piperinedinyloxy.