Fig. 2: Substrate scope of cycloaddition of BCBs with 3,4-dihydroisoquinolines.

Conditions: A (0.1 mmol), B (0.1 mmol) in Et₂O (1.0 mL) under N₂ atmosphere and 5 W LED (λ_max = 365 nm) irradiation at 10 °C, yield of isolated product. ^a10 W instead of 5 W. ^bAfter 12 h, another portion A (0.1 mmol) was added and reacted for further 12 h; ^c10 W LED in THF was used.