Light‐Induced Vicinal Dichlorination of Alkenes Using FeCl3 as the Dichlorination Reagent

We report a ligand‐to‐metal charge‐transfer (LMCT) process that used ferric (III) chloride as efficient chlorination reagent to mediate the vicinal dichlorination of alkenes. Under 420 nm LED light, the easily available and safe ferric (III) chloride could facilitate various alkenes to transform as 1,2‐dichloride compounds with good to excellent yields (19 examples). The strategy showed a more economic protocol than CuCl2, and provided a significant reference for the light‐Induced dichlorination in industrial catalysis. It was found that FeCl3 can directly react with alkenes to give vicinal dichlorides under irradiation of the light, which provides an additive‐free and concise method of using inexpensive FeCl3 as the chlorination reagent to enable vicinal dichlorination of alkenes.