To a 5 mL Shlenck tube containing a PTFE-coated stirring bar was charged with ethyl 2-(phenylsulfonyl)acetate 1a (0.2 mmol, 1.0 equiv), 4-CzIPN (2 mol %), and K3PO4▪3H2O (0.4 mmol, 106 mg, 2.0 equiv). The vessel was then evacuated and filled with nitrogen three times. Then, MeCN (4 mL) was added, followed by the addition of alkyne 2a (0.4 mmol, 2.0 equiv) under nitrogen flow. Finally, the tube was sealed and placed in the photoreactor about 2 cm away from a 10 W 460 nm LEDs light irradiation with a chiller to maintain the temperature at 25 o C. After 12 hours, the reaction mixture was concentrated under reduced pressure and the crude product was purified by column chromatography on silica gel to give the corresponding pure products.