All reagents purchased from Acros, Alfa, Sigma-Aldrich, TCI and VWR were used as supplied. All air and/or water sensitive reactions were carried out under an atmosphere of argon in flame-dried glassware using standard Schlenk techniques. Anhydrous solvents were dried by pre-storing over activated 3 Å (MeOH) or 4 Å (all other solvents) molecular sieves and purged by argon sparging. Blue light irradiation was performed with RGB LED strips (5.4 W). Reactions were monitored by thin-layer chromatography (TLC) on pre-coated aluminum-based plates (TLC Silica gel 60 F254, Supelco). The plates were developed under UV irradiation (254 nm) or with vanillin or KMnO4 staining and subsequent heating. Column chromatography was performed with silica gel (Silica gel 60, irregular 40-63 µm for flash chromatography, VWR Chemicals). H NMR spectra were recorded at room temperature on a 400 MHz Bruker 9.4 Tesla Avance III HD system equipped with a SmartProbe (broad band). Procedure I for the Synthesis of Epoxides 2. Based on a literature procedure. Aqueous 2 M NaOH was added to an aqueous 4 • 10 -4 M EDTA solution (0.3 M with respect to the olefin) until pH 4. The mixture was added to a solution of olefin (1.0 equiv.) in acetonitrile (85 mM with respect to the olefin). Sodium chlorite (3.1 equiv.) was added, the reaction flask was topped with a condenser and the reaction mixture was stirred at 65 °C overnight. The colorless mixture turned yellow. It was cooled to 0 °C, and the mixture was slowly quenched by dropwise addition of an aqueous 1 M Na2S2O3 solution until no more peroxide was detected by starch paper. The colorless quenched mixture was reduced in vacuo before being extracted with CH2Cl2 (3 x 15 ml). The combined organic layers were washed with water and brine, dried over anhydrous Na2SO4, filtered and concentrated in vacuo. The crude was purified by column chromatography to afford the wanted epoxide.