Fig. 4: Scope of electrophiles.

^[a] Reaction conditions: To a solution of o-bromostyrene 1a (0.26 mmol, 1.3 equiv) in THF (0.6 mL) was added n-BuLi (0.26 mmol, 1.3 equiv) −78 °C under argon, the resulting mixture was stirred at −78 °C for 1 h, then 2a (0.2 mmol, 1.0 equiv) in THF (0.2 mL) was added and stirred at −78 °C for 40 min and warm to room temperature for 40 min; then electrophile 7 (1.0 mmol, 5.0 equiv) and 4CzIPN (2 mol%) were added in MeCN (2 mL, 0.1 M) and irradiated by blue LEDs under an argon atmosphere for 20 h; ^[b] The dr was determined by ¹H NMR analysis.