A mixture of the substrate (1 mmol), Sc(OTf)3 (5 mol%) and TMSCN (12 equiv., 12 mmol, 1501 μL) in MeCN (5 mL) was bubbled with oxygen (2 min). It was then stirred at ambient temperature in a 50 mL Schlenk tube under irradiation by 400 nm Luxeon LEDs under aerobic conditions (oxygen balloon). The reaction progress was monitored by TLC and 1 H NMR. When the reaction was completed, the solvent was evaporated, and the crude product was purified by column chromatography on silica gel (see Supplementary Section S6 for details).