A dry 5 mL Schlenk tube containing a stirring bar was charged with N-tosylhydrazone (0.2 mmol, 1.0 equiv.) and K 2 CO 3 (0.4 mmol, 2.0 equiv.). After purging the flask three times under vacuum and three times under argon, it was charged with 2.0 mmol of HFIP (10.0 equiv.) and anhydrous 1,4-Dioxane (0.8 mL), successively. The reaction was kept for 16 h under 40 W 390 nm Kessil lamp reaction setup (the progress can be monitored via TLC). Then, the resulting mixture is concentrated in vacuo. Products were purified via column chromatography with ethyl acetate and hexane as solvents.