Fig. 5: Substrate scope and functional group compatibility of β-gem-diboryl NHPI esters.

Reaction conditions: a 1 (0.2 mmol), 4 (1.5 equiv, 0.3 mmol), Fluoresein (1 mol%, 0.002 mmol), HE (2 equiv, 0.4 mmol), DIPEA (1 equiv, 0.2 mmol), HCOOH (1 equiv, 0.2 mmol), DCM (2 mL) at room temperature, 40 W blue LEDs, 12 h in argon. b 1 (0.2 mmol), 2 (1.5 equiv, 0.3 mmol), Ir(ppy)3 (1 mol%, 0.002 mmol), HE (1.5 equiv, 0.3 mmol), DIPEA (2 equiv, 0.4 mmol), DCE (2 mL) at room temperature, 40 W blue LEDs, 12 h in argon.