Fig. 3. Substrate scope. ^aGeneral reaction conditions: 1a (0.10 mmol), 2a (0.20 mmol), Mes-Acr⁺ (0.005 mmol), TPA (0.010 mmol), and TFA (0.20 mmol) were reacted in dichloromethane (DCM; 2.0 mL) at room temperature under blue LED irradiation for 7 h. Yield is isolated yield unless otherwise noted. ^b5 equiv. of the aldehyde was used with the reaction time 13 h. ^cReaction time was 3 h. ^dReaction time was 5 h.